diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 68d1339..a498575 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -275,8 +275,10 @@ export default function App() {
   // "Focus this channel in the manager": jump to the Channels page and seed its name filter
   // so the channel is isolated. Cleared when leaving the page so it doesn't re-apply later.
   const [focusChannelName, setFocusChannelName] = useState<string | null>(null);
+  const [focusChannelToken, setFocusChannelToken] = useState(0);
   const focusChannel = (name: string) => {
     setFocusChannelName(name);
+    setFocusChannelToken((n) => n + 1); // re-seed even when the same channel is re-focused
     setChannelsView("subscribed"); // the name filter applies to the subscriptions table
     setPage("channels");
   };
@@ -803,6 +805,7 @@ export default function App() {
               canWrite={meQuery.data!.can_write}
               isAdmin={meQuery.data!.role === "admin"}
               focusChannelName={focusChannelName}
+              focusChannelToken={focusChannelToken}
               onFocusChannel={focusChannel}
               statusFilter={channelFilter}
               setStatusFilter={setChannelFilter}
diff --git a/frontend/src/components/AdminUsers.tsx b/frontend/src/components/AdminUsers.tsx
index 20b69af..d112173 100644
--- a/frontend/src/components/AdminUsers.tsx
+++ b/frontend/src/components/AdminUsers.tsx
@@ -52,19 +52,25 @@ function UsersRoles({ me }: { me: Me }) {
   const qc = useQueryClient();
   const confirm = useConfirm();
   const q = useQuery({ queryKey: ["admin-users"], queryFn: api.adminUsers });
+  // Which row currently has an action in flight, so we disable ONLY that row's button (mutations
+  // are single-flight, so one id suffices) rather than greying every row (SC1).
+  const [pendingId, setPendingId] = useState<number | null>(null);
   const setRole = useMutation({
     mutationFn: ({ id, role }: { id: number; role: "user" | "admin"; email: string }) =>
       api.setUserRole(id, role),
+    onMutate: (vars) => setPendingId(vars.id),
     onSuccess: (_d, vars) => {
       qc.invalidateQueries({ queryKey: ["admin-users"] });
       notify({ level: "success", message: t("users.roles.updated", { email: vars.email }) });
     },
+    onSettled: () => setPendingId(null),
     // Errors (e.g. last-admin / self) surface via the global error dialog with the server's detail.
   });
 
   const suspend = useMutation({
     mutationFn: ({ id, suspended }: { id: number; suspended: boolean; email: string }) =>
       api.setUserSuspended(id, suspended),
+    onMutate: (vars) => setPendingId(vars.id),
     onSuccess: (_d, vars) => {
       qc.invalidateQueries({ queryKey: ["admin-users"] });
       notify({
@@ -74,14 +80,17 @@ function UsersRoles({ me }: { me: Me }) {
         }),
       });
     },
+    onSettled: () => setPendingId(null),
     // Guards (demo / self / last admin) surface via the global error dialog.
   });
   const del = useMutation({
     mutationFn: ({ id }: { id: number; email: string }) => api.adminDeleteUser(id),
+    onMutate: (vars) => setPendingId(vars.id),
     onSuccess: (_d, vars) => {
       qc.invalidateQueries({ queryKey: ["admin-users"] });
       notify({ level: "success", message: t("users.delete.done", { email: vars.email }) });
     },
+    onSettled: () => setPendingId(null),
   });
 
   const onToggle = async (u: AdminUserRow) => {
@@ -162,7 +171,7 @@ function UsersRoles({ me }: { me: Me }) {
                 >
                   <button
                     onClick={() => onToggle(u)}
-                    disabled={u.is_demo || self || setRole.isPending}
+                    disabled={u.is_demo || self || pendingId === u.id}
                     className="shrink-0 glass-card glass-hover inline-flex items-center gap-1 px-2.5 py-1.5 rounded-lg text-xs disabled:opacity-40 transition"
                   >
                     <Shield className="w-3.5 h-3.5" />
@@ -182,7 +191,7 @@ function UsersRoles({ me }: { me: Me }) {
                 >
                   <button
                     onClick={() => onSuspend(u)}
-                    disabled={u.is_demo || self || suspend.isPending}
+                    disabled={u.is_demo || self || pendingId === u.id}
                     aria-label={u.is_suspended ? t("users.suspend.undoAction") : t("users.suspend.action")}
                     className={`shrink-0 p-1.5 rounded-lg border disabled:opacity-40 transition ${
                       u.is_suspended
@@ -196,7 +205,7 @@ function UsersRoles({ me }: { me: Me }) {
                 <Tooltip hint={u.is_demo || self ? t("users.delete.locked") : t("users.delete.action")}>
                   <button
                     onClick={() => onDelete(u)}
-                    disabled={u.is_demo || self || del.isPending}
+                    disabled={u.is_demo || self || pendingId === u.id}
                     aria-label={t("users.delete.action")}
                     className="shrink-0 p-1.5 rounded-lg border border-border text-muted hover:text-red-400 disabled:opacity-40 transition"
                   >
@@ -217,6 +226,7 @@ function UsersRoles({ me }: { me: Me }) {
 function AdminInvites() {
   const { t } = useTranslation();
   const qc = useQueryClient();
+  const confirm = useConfirm();
   const invites = useQuery({ queryKey: ["admin-invites"], queryFn: () => api.adminInvites() });
   const [newEmail, setNewEmail] = useState("");
   const refresh = () => {
@@ -233,9 +243,21 @@ function AdminInvites() {
   });
   const deny = useMutation({
     mutationFn: (id: number) => api.denyInvite(id),
-    onSuccess: refresh,
+    onSuccess: (_d, _id) => {
+      refresh();
+      notify({ level: "success", message: t("settings.invites.denied") });
+    },
     onError: () => notify({ level: "error", message: t("settings.invites.denyFailed") }),
   });
+  const onDeny = async (i: { id: number; email: string }) => {
+    const ok = await confirm({
+      title: t("settings.invites.denyTitle"),
+      message: t("settings.invites.denyConfirm", { email: i.email }),
+      confirmLabel: t("settings.invites.deny"),
+      danger: true,
+    });
+    if (ok) deny.mutate(i.id);
+  };
   const add = useMutation({
     mutationFn: (email: string) => api.addInvite(email),
     onSuccess: (_d, email) => {
@@ -261,7 +283,7 @@ function AdminInvites() {
               key={i.id}
               inv={i}
               onApprove={() => approve.mutate({ id: i.id, email: i.email })}
-              onDeny={() => deny.mutate(i.id)}
+              onDeny={() => onDeny(i)}
               busy={approve.isPending || deny.isPending}
             />
           ))}
@@ -329,9 +351,21 @@ function AdminDemo() {
   });
   const remove = useMutation({
     mutationFn: (id: number) => api.removeDemoWhitelist(id),
-    onSuccess: () => qc.invalidateQueries({ queryKey: ["demo-whitelist"] }),
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ["demo-whitelist"] });
+      notify({ level: "success", message: t("settings.demo.removed") });
+    },
     onError: () => notify({ level: "error", message: t("settings.demo.removeFailed") }),
   });
+  const onRemove = async (r: { id: number; email: string }) => {
+    const ok = await confirm({
+      title: t("settings.demo.removeTitle"),
+      message: t("settings.demo.removeConfirm", { email: r.email }),
+      confirmLabel: t("settings.demo.remove"),
+      danger: true,
+    });
+    if (ok) remove.mutate(r.id);
+  };
   const reset = useMutation({
     mutationFn: () => api.resetDemo(),
     onSuccess: (r: { playlists_seeded: number }) =>
@@ -362,7 +396,7 @@ function AdminDemo() {
               </div>
               <Tooltip hint={t("settings.demo.removeHint")}>
                 <button
-                  onClick={() => remove.mutate(r.id)}
+                  onClick={() => onRemove(r)}
                   disabled={remove.isPending}
                   className="shrink-0 p-1.5 rounded-lg border border-border text-muted hover:text-red-400 disabled:opacity-50 transition"
                   aria-label={t("settings.demo.remove")}
diff --git a/frontend/src/components/Channels.tsx b/frontend/src/components/Channels.tsx
index 85b7f93..b4e2043 100644
--- a/frontend/src/components/Channels.tsx
+++ b/frontend/src/components/Channels.tsx
@@ -48,6 +48,7 @@ export default function Channels({
   onFilterByTag,
   onFocusChannel,
   focusChannelName,
+  focusChannelToken,
   statusFilter,
   setStatusFilter,
   view,
@@ -61,6 +62,9 @@ export default function Channels({
   onFilterByTag: (tagId: number, name: string) => void;
   onFocusChannel: (name: string) => void;
   focusChannelName: string | null;
+  // Bumped every time a focus-channel intent is (re-)issued, so re-clicking the same channel
+  // re-seeds the search box even when the name is unchanged.
+  focusChannelToken: number;
   statusFilter: ChannelStatusFilter;
   setStatusFilter: (f: ChannelStatusFilter) => void;
   // The active tab lives in App so navigation intents that target the subscriptions table
@@ -92,6 +96,10 @@ export default function Channels({
     qc.invalidateQueries({ queryKey: ["channels"] });
     qc.invalidateQueries({ queryKey: ["tags"] });
     qc.invalidateQueries({ queryKey: ["my-status"] });
+    // FB2: syncing subscriptions can change the feed immediately — newly-followed channels may
+    // already have videos in the shared catalog, so refresh the feed too (not just the manager).
+    qc.invalidateQueries({ queryKey: ["feed"] });
+    qc.invalidateQueries({ queryKey: ["feed-count"] });
   };
 
   const userTags = (tagsQuery.data ?? []).filter((t) => !t.system);
@@ -189,7 +197,8 @@ export default function Channels({
   // A focus-channel intent (header "without full history" / tag manager) seeds the search box.
   useEffect(() => {
     if (focusChannelName) setSearch(focusChannelName);
-  }, [focusChannelName]);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [focusChannelToken]);
   // The header's reset intent clears the search + tag chips (skip the initial mount).
   const resetRef = useRef(filtersResetToken);
   useEffect(() => {
diff --git a/frontend/src/components/ChatDock.tsx b/frontend/src/components/ChatDock.tsx
index 87dbb0d..6304563 100644
--- a/frontend/src/components/ChatDock.tsx
+++ b/frontend/src/components/ChatDock.tsx
@@ -3,7 +3,7 @@ import { useTranslation } from "react-i18next";
 import { useQueryClient } from "@tanstack/react-query";
 import { ChevronDown, ChevronUp, X } from "lucide-react";
 import { closeChat, initDock, notifyIncoming, toggleMinimize, useDockChats, type DockChat } from "../lib/chatDock";
-import { onMessage } from "../lib/messagesSocket";
+import { onMessage, onUnread } from "../lib/messagesSocket";
 import * as e2ee from "../lib/e2ee";
 import Avatar from "./Avatar";
 import ChatThread from "./ChatThread";
@@ -39,6 +39,16 @@ export default function ChatDock({ meId }: { meId: number }) {
     [qc, meId]
   );
 
+  // Live badge sync: another tab/device read a thread → refresh this tab's unread count + list.
+  useEffect(
+    () =>
+      onUnread(() => {
+        qc.invalidateQueries({ queryKey: ["message-unread"] });
+        qc.invalidateQueries({ queryKey: ["conversations"] });
+      }),
+    [qc]
+  );
+
   if (chats.length === 0) return null;
   return (
     <div className="fixed bottom-0 right-0 z-40 flex flex-row-reverse items-end gap-3 p-4 pointer-events-none">
diff --git a/frontend/src/components/ChatThread.tsx b/frontend/src/components/ChatThread.tsx
index 58b6816..c059e13 100644
--- a/frontend/src/components/ChatThread.tsx
+++ b/frontend/src/components/ChatThread.tsx
@@ -6,12 +6,10 @@ import { api, HttpError, type Message, type MessageUser } from "../lib/api";
 import { useLiveQuery } from "../lib/useLiveQuery";
 import { relativeTime } from "../lib/format";
 import { notify } from "../lib/notifications";
-import { partnerPub, useKeyState } from "../lib/messaging";
+import { partnerPub, POLL_MS, useKeyState } from "../lib/messaging";
 import * as e2ee from "../lib/e2ee";
 import KeyGate from "./KeyGate";
 
-const POLL_MS = 20000; // safety net; live updates arrive over the WebSocket
-
 // The message list + composer for one conversation, shared by the full Messages page and the
 // floating dock window. Handles client-side decryption and encrypt-on-send; the surrounding
 // chrome (back button / minimize / close) is the caller's. Self-contained key gating: prompts
@@ -66,13 +64,20 @@ export default function ChatThread({
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [q.dataUpdatedAt, ready, isSystem, partnerId, t]);
 
-  // Opening / refreshing the thread marks incoming messages read, so clear the badges.
+  // Opening the thread (or a new incoming message arriving) marks messages read server-side, so
+  // refresh the badges — but ONLY when the incoming-message count actually changed, not on every
+  // 20s poll (which would needlessly refetch /conversations + /unread_count each tick).
+  const lastIncoming = useRef(-1);
   useEffect(() => {
-    if (q.dataUpdatedAt) {
+    if (!q.dataUpdatedAt) return;
+    const incoming = (q.data?.items ?? []).filter((m) => m.recipient_id === meId).length;
+    if (incoming !== lastIncoming.current) {
+      lastIncoming.current = incoming;
       qc.invalidateQueries({ queryKey: ["conversations"] });
       qc.invalidateQueries({ queryKey: ["message-unread"] });
     }
-  }, [q.dataUpdatedAt, qc]);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [q.dataUpdatedAt, meId, qc]);
 
   // Scroll to the newest message when the count changes (open / new message) — NOT on `plain`,
   // which gets a fresh object on every poll's decrypt pass and would yank a scrolled-up reader
diff --git a/frontend/src/components/ConfigPanel.tsx b/frontend/src/components/ConfigPanel.tsx
index 680586a..730dd0d 100644
--- a/frontend/src/components/ConfigPanel.tsx
+++ b/frontend/src/components/ConfigPanel.tsx
@@ -38,15 +38,23 @@ export default function ConfigPanel() {
   // clearing the field, since an empty secret field means "leave unchanged").
   const [secretReset, setSecretReset] = useState<Record<string, boolean>>({});
   const [saveState, setSaveState] = useState<SaveState>("idle");
+  // Bumped after our own save so the draft re-seeds from fresh server values; a plain mid-edit
+  // refetch does NOT (see the effect below).
+  const [reseedToken, setReseedToken] = useState(0);
   // One tab per config group (persisted). Called before the loading guard so hook order is
   // stable; the active id is clamped to a real group at render time once data has loaded.
   const [tab, setTab] = usePersistedTab(LS.configTab);
 
-  // Re-seed the draft whenever the server data changes (initial load + after a save/reset).
+  // A stable signature of the config SHAPE — changes only when keys are added/removed, not when an
+  // unchanged refetch produces a new baseline object. Re-seed the draft on a shape change (initial
+  // load, registry change) or an explicit post-save bump — so a refetch that resolves mid-edit
+  // (e.g. an invalidation) can no longer clobber the admin's in-progress draft (CB2).
+  const dataVersion = useMemo(() => items.map((i) => i.key).join("|"), [items]);
   useEffect(() => {
     setDraft(baseline);
     setSecretReset({});
-  }, [baseline]);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [dataVersion, reseedToken]);
 
   const isDirty = (it: ConfigItem): boolean => {
     if (it.secret) return (draft[it.key] ?? "").trim() !== "" || !!secretReset[it.key];
@@ -67,12 +75,16 @@ export default function ConfigPanel() {
         } else if (it.type === "bool") {
           await api.setConfig(key, raw === "true");
         } else if (raw === "") {
-          if (it.is_set) await api.resetConfig(key); // cleared → fall back to default
+          // allow_empty keys treat a blank as an explicit empty value (e.g. disable smtp_user /
+          // youtube_api_proxy) rather than resetting to the env default (AB3).
+          if (it.allow_empty) await api.setConfig(key, "");
+          else if (it.is_set) await api.resetConfig(key); // cleared → fall back to default
         } else {
           await api.setConfig(key, it.type === "int" ? Number(raw) : raw);
         }
       }
       await qc.invalidateQueries({ queryKey: ["admin-config"] });
+      setReseedToken((n) => n + 1); // re-seed the draft from the saved server state
       setSaveState("saved");
       setTimeout(() => setSaveState((s) => (s === "saved" ? "idle" : s)), 2500);
     } catch {
diff --git a/frontend/src/components/Messages.tsx b/frontend/src/components/Messages.tsx
index 769256e..86b20f7 100644
--- a/frontend/src/components/Messages.tsx
+++ b/frontend/src/components/Messages.tsx
@@ -5,7 +5,7 @@ import { ArrowLeft, ShieldCheck, SquarePen, ExternalLink } from "lucide-react";
 import { api, type Conversation, type MessageUser } from "../lib/api";
 import { useLiveQuery } from "../lib/useLiveQuery";
 import { relativeTime } from "../lib/format";
-import { partnerPub, SYSTEM_ID, useKeyState } from "../lib/messaging";
+import { partnerPub, POLL_MS, SYSTEM_ID, useKeyState } from "../lib/messaging";
 import { useHistorySubview } from "../lib/history";
 import { openChat } from "../lib/chatDock";
 import * as e2ee from "../lib/e2ee";
@@ -13,8 +13,6 @@ import Avatar from "./Avatar";
 import KeyGate from "./KeyGate";
 import ChatThread from "./ChatThread";
 
-const POLL_MS = 20000;
-
 type View = "list" | "new" | { partnerId: number; name?: string; avatar?: string | null; system?: boolean };
 
 export default function Messages({ meId }: { meId: number }) {
diff --git a/frontend/src/components/PlayerModal.tsx b/frontend/src/components/PlayerModal.tsx
index 1f663ae..ad173dd 100644
--- a/frontend/src/components/PlayerModal.tsx
+++ b/frontend/src/components/PlayerModal.tsx
@@ -107,6 +107,10 @@ export default function PlayerModal({
   const mountRef = useRef<HTMLDivElement | null>(null);
   const playerRef = useRef<any>(null);
   const autoMarkedRef = useRef(false);
+  // Bound consecutive unplayable items so an auto-advancing queue (esp. loop=all) can't spin over a
+  // run of dead videos — after the cap we stop on the error overlay instead of skipping forever.
+  const MAX_CONSECUTIVE_ERRORS = 3;
+  const errorStreakRef = useRef(0);
   // Keyboard/wheel controls. We keep focus on the modal card (not the cross-origin player
   // iframe) so F / Space / Esc keep working until the user clicks into YouTube's native
   // controls; the interaction overlay below also stops the iframe stealing focus on a video
@@ -502,6 +506,7 @@ export default function PlayerModal({
           onStateChange: (e: any) => {
             // 1 === playing → sync the navigated-to video's title/author for display.
             if (e?.data === 1) {
+              errorStreakRef.current = 0; // a successful play breaks any unplayable run
               const p = playerRef.current;
               const d = p && typeof p.getVideoData === "function" ? p.getVideoData() : null;
               if (d) setLiveData({ title: d.title, author: d.author });
@@ -517,17 +522,47 @@ export default function PlayerModal({
           },
           // The embed couldn't play this video (embedding disabled, removed, private…).
           // Surface our own message + an "Open on YouTube" escape hatch.
-          onError: (e: any) => setPlayerError(typeof e?.data === "number" ? e.data : -1),
+          onError: (e: any) => {
+            setPlayerError(typeof e?.data === "number" ? e.data : -1);
+            // The IFrame API fires onError (not 'ended') for an unplayable item, so advanceOnEnd()
+            // never runs and an auto-advancing queue would freeze here. Skip forward instead — but
+            // bounded, so a run of dead items (or loop=all over a broken queue) can't spin. We do
+            // NOT mark the broken video watched (only the ended-handler does that).
+            if (currentIdRef.current !== id) return; // a navigated description-link error: leave the queue alone
+            const { autoMode: a } = modeRef.current;
+            const { queue: q } = navRef.current;
+            if (a === "off" || !q || q.length <= 1) return;
+            errorStreakRef.current += 1;
+            if (errorStreakRef.current >= MAX_CONSECUTIVE_ERRORS) return; // give up; leave the overlay
+            advanceOnEnd();
+          },
         },
       });
     });
 
     // Periodic checkpoint so progress (and auto-watch) survive a crash/refresh.
     const timer = window.setInterval(persist, 5000);
+    // Save on page unload too (F5/close/navigate): effect cleanup doesn't run on a full reload, so
+    // without this the resume point lags up to 5s (a seek right before F5 would be lost). A keepalive
+    // beacon so the POST survives the unload. Only for the library item we opened with — a navigated
+    // description-link video may not be in this user's library (the server would 404).
+    const onHide = () => {
+      const p = playerRef.current;
+      if (!p || typeof p.getCurrentTime !== "function" || currentIdRef.current !== id) return;
+      try {
+        const cur = p.getCurrentTime();
+        const dur = typeof p.getDuration === "function" ? p.getDuration() : 0;
+        if (cur > 0 && dur > 0) api.saveProgressBeacon(id, cur, dur);
+      } catch {
+        /* player tearing down */
+      }
+    };
+    window.addEventListener("pagehide", onHide);
 
     return () => {
       cancelled = true;
       window.clearInterval(timer);
+      window.removeEventListener("pagehide", onHide);
       // Final flush, then refresh the feed + playlists so resume bars reflect this session.
       Promise.resolve(persist()).finally(() => {
         qc.invalidateQueries({ queryKey: ["feed"] });
diff --git a/frontend/src/components/Scheduler.tsx b/frontend/src/components/Scheduler.tsx
index e399ccd..8a227f2 100644
--- a/frontend/src/components/Scheduler.tsx
+++ b/frontend/src/components/Scheduler.tsx
@@ -318,11 +318,33 @@ export default function Scheduler() {
   });
   const data = q.data;
 
-  // Tick once a second so the per-job countdowns move between polls.
+  // Tick once a second so the per-job countdowns move between polls — but only while the tab is
+  // visible; a hidden tab doesn't need to re-render the whole page every second (SB3).
   const [, setTick] = useState(0);
   useEffect(() => {
-    const id = setInterval(() => setTick((n) => n + 1), 1000);
-    return () => clearInterval(id);
+    let id: ReturnType<typeof setInterval> | undefined;
+    const start = () => {
+      if (id == null) id = setInterval(() => setTick((n) => n + 1), 1000);
+    };
+    const stop = () => {
+      if (id != null) {
+        clearInterval(id);
+        id = undefined;
+      }
+    };
+    const onVisibility = () => {
+      if (document.hidden) stop();
+      else {
+        setTick((n) => n + 1); // snap the countdown to the correct value on return
+        start();
+      }
+    };
+    onVisibility(); // honor the current visibility on mount
+    document.addEventListener("visibilitychange", onVisibility);
+    return () => {
+      stop();
+      document.removeEventListener("visibilitychange", onVisibility);
+    };
   }, []);
 
   const pauseResume = useMutation({
diff --git a/frontend/src/i18n/locales/de/downloads.json b/frontend/src/i18n/locales/de/downloads.json
index fd7b4c8..001f96e 100644
--- a/frontend/src/i18n/locales/de/downloads.json
+++ b/frontend/src/i18n/locales/de/downloads.json
@@ -185,5 +185,17 @@
     "added": "Hinzugefügt",
     "user": "Nutzer"
   },
-  "clipBadge": "Clip"
+  "clipBadge": "Clip",
+  "errors": {
+    "quota": {
+      "max_bytes": "Dein Download-Speicherkontingent ist aufgebraucht ({{size}} GB). Gib zuerst Speicher frei.",
+      "max_jobs": "Du hast dein Download-Limit erreicht ({{limit}} Objekte). Entferne zuerst einige.",
+      "generic": "Download-Kontingent überschritten."
+    },
+    "edit": {
+      "empty_edit": "Wähle zuerst einen Zuschneidebereich oder Ausschnitt.",
+      "source_not_ready": "Der Quell-Download ist noch nicht bearbeitbar.",
+      "generic": "Dieser Schnitt konnte nicht erstellt werden."
+    }
+  }
 }
diff --git a/frontend/src/i18n/locales/de/settings.json b/frontend/src/i18n/locales/de/settings.json
index 3425b9f..77b9755 100644
--- a/frontend/src/i18n/locales/de/settings.json
+++ b/frontend/src/i18n/locales/de/settings.json
@@ -124,7 +124,10 @@
     "resetTitle": "Demo-Zustand zurücksetzen?",
     "resetConfirm": "Dies löscht alles, was das Demo-Konto angesammelt hat — Playlists, ausgeblendete/angesehene/gespeicherte Videos und Einstellungen — und legt ein paar Beispiel-Playlists neu an. Es kann nicht rückgängig gemacht werden.",
     "resetDone": "Demo zurückgesetzt — {{count}} Beispiel-Playlist(s) angelegt",
-    "resetFailed": "Das Demo-Konto konnte nicht zurückgesetzt werden"
+    "resetFailed": "Das Demo-Konto konnte nicht zurückgesetzt werden",
+    "removed": "Von der Demo-Whitelist entfernt",
+    "removeTitle": "Demo-Zugang entfernen?",
+    "removeConfirm": "{{email}} von der Demo-Whitelist entfernen? Der Zugang zum Demo-Konto ist dann nicht mehr möglich."
   },
   "invites": {
     "title": "Zugriffsanfragen",
@@ -141,6 +144,9 @@
     "approveHint": "Genehmigen — setzt diese E-Mail auf die Whitelist und benachrichtigt sie per E-Mail, dass sie dabei sind.",
     "approve": "Genehmigen",
     "denyHint": "Diese Anfrage ablehnen.",
-    "deny": "Ablehnen"
+    "deny": "Ablehnen",
+    "denied": "Anfrage abgelehnt",
+    "denyTitle": "Zugriffsanfrage ablehnen?",
+    "denyConfirm": "Die Zugriffsanfrage von {{email}} ablehnen?"
   }
 }
diff --git a/frontend/src/i18n/locales/en/downloads.json b/frontend/src/i18n/locales/en/downloads.json
index 0b404dc..896007f 100644
--- a/frontend/src/i18n/locales/en/downloads.json
+++ b/frontend/src/i18n/locales/en/downloads.json
@@ -185,5 +185,17 @@
     "added": "Added",
     "user": "User"
   },
-  "clipBadge": "Clip"
+  "clipBadge": "Clip",
+  "errors": {
+    "quota": {
+      "max_bytes": "You've used your download storage quota ({{size}} GB). Free up space first.",
+      "max_jobs": "You've reached your download limit ({{limit}} items). Remove some first.",
+      "generic": "Download quota exceeded."
+    },
+    "edit": {
+      "empty_edit": "Choose a trim range or crop area first.",
+      "source_not_ready": "The source download isn't ready to edit.",
+      "generic": "That edit couldn't be created."
+    }
+  }
 }
diff --git a/frontend/src/i18n/locales/en/settings.json b/frontend/src/i18n/locales/en/settings.json
index c6c4ac0..6b97891 100644
--- a/frontend/src/i18n/locales/en/settings.json
+++ b/frontend/src/i18n/locales/en/settings.json
@@ -124,7 +124,10 @@
     "resetTitle": "Reset demo state?",
     "resetConfirm": "This clears everything the demo account has accumulated — playlists, hidden/watched/saved videos and settings — and re-seeds a few sample playlists. It can't be undone.",
     "resetDone": "Demo reset — {{count}} sample playlist(s) seeded",
-    "resetFailed": "Couldn't reset the demo account"
+    "resetFailed": "Couldn't reset the demo account",
+    "removed": "Removed from the demo whitelist",
+    "removeTitle": "Remove demo access?",
+    "removeConfirm": "Remove {{email}} from the demo whitelist? They'll no longer be able to enter the demo account."
   },
   "invites": {
     "title": "Access requests",
@@ -141,6 +144,9 @@
     "approveHint": "Approve — whitelist this email and email them they're in.",
     "approve": "Approve",
     "denyHint": "Deny this request.",
-    "deny": "Deny"
+    "deny": "Deny",
+    "denied": "Request denied",
+    "denyTitle": "Deny access request?",
+    "denyConfirm": "Deny the access request from {{email}}?"
   }
 }
diff --git a/frontend/src/i18n/locales/hu/downloads.json b/frontend/src/i18n/locales/hu/downloads.json
index b7e61de..61cf56b 100644
--- a/frontend/src/i18n/locales/hu/downloads.json
+++ b/frontend/src/i18n/locales/hu/downloads.json
@@ -185,5 +185,17 @@
     "added": "Hozzáadva",
     "user": "Felhasználó"
   },
-  "clipBadge": "Klip"
+  "clipBadge": "Klip",
+  "errors": {
+    "quota": {
+      "max_bytes": "Elfogyott a letöltési tárhelykereted ({{size}} GB). Előbb szabadíts fel helyet.",
+      "max_jobs": "Elérted a letöltési korlátodat ({{limit}} elem). Előbb távolíts el néhányat.",
+      "generic": "Túllépted a letöltési kvótát."
+    },
+    "edit": {
+      "empty_edit": "Előbb válassz vágási tartományt vagy körbevágási területet.",
+      "source_not_ready": "A forrásletöltés még nem szerkeszthető.",
+      "generic": "Ezt a vágást nem sikerült létrehozni."
+    }
+  }
 }
diff --git a/frontend/src/i18n/locales/hu/settings.json b/frontend/src/i18n/locales/hu/settings.json
index 1048ae0..99bd459 100644
--- a/frontend/src/i18n/locales/hu/settings.json
+++ b/frontend/src/i18n/locales/hu/settings.json
@@ -124,7 +124,10 @@
     "resetTitle": "Visszaállítod a demo állapotot?",
     "resetConfirm": "Ez törli mindazt, amit a demo fiók összegyűjtött — lejátszási listák, elrejtett/megnézett/mentett videók és beállítások —, és újra létrehoz pár minta lejátszási listát. Nem vonható vissza.",
     "resetDone": "Demo visszaállítva — {{count}} minta lejátszási lista létrehozva",
-    "resetFailed": "Nem sikerült visszaállítani a demo fiókot"
+    "resetFailed": "Nem sikerült visszaállítani a demo fiókot",
+    "removed": "Eltávolítva a demo fehérlistáról",
+    "removeTitle": "Visszavonod a demo hozzáférést?",
+    "removeConfirm": "Eltávolítod {{email}} címet a demo fehérlistáról? Többé nem tud belépni a demo fiókba."
   },
   "invites": {
     "title": "Hozzáférési kérelmek",
@@ -141,6 +144,9 @@
     "approveHint": "Jóváhagyás — fehérlistára teszi ezt az e-mailt és e-mailben értesíti őket, hogy bekerültek.",
     "approve": "Jóváhagyás",
     "denyHint": "Kérelem elutasítása.",
-    "deny": "Elutasítás"
+    "deny": "Elutasítás",
+    "denied": "Kérelem elutasítva",
+    "denyTitle": "Elutasítod a hozzáférési kérelmet?",
+    "denyConfirm": "Elutasítod {{email}} hozzáférési kérelmét?"
   }
 }
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 53e0de2..296d821 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -209,13 +209,35 @@ export interface VersionInfo {
 class HttpError extends Error {
   status: number;
   detail?: string; // server-provided reason (FastAPI's `detail`), when present
-  constructor(status: number, detail?: string) {
+  detailData?: any; // structured detail ({ code, reason, ... }) when the server sent an object
+  constructor(status: number, detail?: string, detailData?: any) {
     super(detail || `HTTP ${status}`);
     this.status = status;
     this.detail = detail;
+    this.detailData = detailData;
   }
 }
 
+// Localize a STRUCTURED server error ({ code, reason, ... }) into the user's language. FastAPI
+// usually returns a plain string `detail`, but some routes (e.g. download quota/edit) return a
+// structured object with an i18n reason key + numbers so HU/DE users don't get hardcoded English
+// with a dot-decimal separator. Falls back to a generic message for unknown shapes.
+function localizeDetail(d: any): string {
+  const t = i18n.t.bind(i18n);
+  if (d?.code === "quota") {
+    if (d.reason === "max_bytes") {
+      const gb = new Intl.NumberFormat(i18n.language, { maximumFractionDigits: 1 }).format(
+        (d.limit || 0) / 1_073_741_824,
+      );
+      return t("downloads.errors.quota.max_bytes", { size: gb });
+    }
+    if (d.reason === "max_jobs") return t("downloads.errors.quota.max_jobs", { limit: d.limit });
+    return t("downloads.errors.quota.generic");
+  }
+  if (d?.code === "edit") return t(`downloads.errors.edit.${d.reason}`, t("downloads.errors.edit.generic"));
+  return t("errors.generic");
+}
+
 // A single, self-resolving "connection lost" status: while the server is unreachable we
 // show one sticky, transient (non-persisted) notice; the moment any request reaches the
 // server again we remove it. This makes good on its "clears once it's back" copy and keeps
@@ -337,9 +359,14 @@ async function req(url: string, opts: RequestInit = {}, cfg: ReqConfig = {}): Pr
     if (!r.ok) {
       // Capture the server's reason (FastAPI returns `{ detail }`) so callers can react.
       let detail: string | undefined;
+      let detailData: any;
       try {
         const body = await r.json();
         if (body && typeof body.detail === "string") detail = body.detail;
+        else if (body && body.detail && typeof body.detail === "object") {
+          detailData = body.detail;
+          detail = localizeDetail(body.detail); // structured error → localized message
+        }
       } catch {
         /* no JSON body */
       }
@@ -361,7 +388,7 @@ async function req(url: string, opts: RequestInit = {}, cfg: ReqConfig = {}): Pr
       } else if (r.status === 400 || r.status === 409 || r.status === 422) {
         reportError(detail);
       }
-      throw new HttpError(r.status, detail);
+      throw new HttpError(r.status, detail, detailData);
     }
     return r.status === 204 ? null : r.json();
   }
@@ -601,6 +628,7 @@ export interface ConfigItem {
   min: number | null;
   max: number | null;
   is_set: boolean; // a DB override row exists (else using the env/config default)
+  allow_empty?: boolean; // if true, a blank field stores "" (explicit empty) rather than resetting
   value?: string | number | boolean; // non-secret: effective value
   default?: string | number | boolean; // non-secret: env/config default
   default_is_set?: boolean; // secret: whether an env default exists
@@ -1074,6 +1102,30 @@ export const api = {
       },
       { idempotent: true }
     ),
+  // Fire-and-forget YT progress save that survives page unload (F5/close/navigate) — mirrors
+  // plexProgressBeacon. A normal fetch is cancelled on unload and React effect cleanup doesn't run
+  // on a full reload, so the last position (esp. right after a seek) would be lost; keepalive lets
+  // it complete.
+  saveProgressBeacon: (id: string, positionSeconds: number, durationSeconds: number): void => {
+    const active = getActiveAccount();
+    try {
+      void fetch(`/api/videos/${encodeURIComponent(id)}/progress`, {
+        method: "POST",
+        keepalive: true,
+        credentials: "include",
+        headers: {
+          "Content-Type": "application/json",
+          ...(active != null ? { [ACTIVE_ACCOUNT_HEADER]: String(active) } : {}),
+        },
+        body: JSON.stringify({
+          position_seconds: Math.floor(positionSeconds),
+          duration_seconds: Math.floor(durationSeconds),
+        }),
+      }).catch(() => {});
+    } catch {
+      /* ignore */
+    }
+  },
   videoDetail: (id: string): Promise<VideoDetail> => req(`/api/videos/${id}`),
   pauseSync: () => req("/api/sync/pause", { method: "POST" }),
   resumeSync: () => req("/api/sync/resume", { method: "POST" }),
diff --git a/frontend/src/lib/e2ee.ts b/frontend/src/lib/e2ee.ts
index f0d5c0f..003d552 100644
--- a/frontend/src/lib/e2ee.ts
+++ b/frontend/src/lib/e2ee.ts
@@ -112,6 +112,15 @@ export async function loadFromDevice(userId: number): Promise<boolean> {
   return false;
 }
 
+// Install a freshly-imported private key as the current identity: drop any derived conversation
+// keys, persist it to this device, and notify unlock subscribers. Shared by setup() and unlock().
+async function installKey(userId: number, key: CryptoKey): Promise<void> {
+  privKey = key;
+  convKeys.clear();
+  await idbPut(userId, key);
+  emitUnlock();
+}
+
 // First-run setup: generate a keypair, wrap the private key with the passphrase, persist a
 // non-extractable copy locally, and return the bundle to upload to the server.
 export async function setup(userId: number, passphrase: string): Promise<KeySetup> {
@@ -128,10 +137,7 @@ export async function setup(userId: number, passphrase: string): Promise<KeySetu
   const keyCheck = await subtle.encrypt({ name: "AES-GCM", iv: bsrc(checkIv) }, wrapKey, bsrc(enc.encode("ok")));
   const spki = await subtle.exportKey("spki", kp.publicKey);
 
-  privKey = await importPrivate(pkcs8);
-  convKeys.clear();
-  await idbPut(userId, privKey);
-  emitUnlock();
+  await installKey(userId, await importPrivate(pkcs8));
   return {
     public_key: b64(spki),
     wrapped_private_key: b64(wrapped),
@@ -154,10 +160,7 @@ export async function unlock(userId: number, passphrase: string, bundle: MyKeyBu
     wrapKey,
     bsrc(ub64(bundle.wrapped_private_key))
   );
-  privKey = await importPrivate(pkcs8);
-  convKeys.clear();
-  await idbPut(userId, privKey);
-  emitUnlock();
+  await installKey(userId, await importPrivate(pkcs8));
 }
 
 // --- per-conversation encryption ---
diff --git a/frontend/src/lib/messagesSocket.ts b/frontend/src/lib/messagesSocket.ts
index 7a03148..37bb431 100644
--- a/frontend/src/lib/messagesSocket.ts
+++ b/frontend/src/lib/messagesSocket.ts
@@ -11,8 +11,10 @@ interface IncomingMessage {
   to?: MessageUser;
 }
 type Handler = (e: IncomingMessage) => void;
+type UnreadHandler = () => void;
 
 const handlers = new Set<Handler>();
+const unreadHandlers = new Set<UnreadHandler>();
 let ws: WebSocket | null = null;
 let started = false;
 let backoff = 1000;
@@ -21,7 +23,9 @@ let reconnectTimer: ReturnType<typeof setTimeout> | null = null;
 function url(): string {
   const proto = location.protocol === "https:" ? "wss" : "ws";
   // A WebSocket can't carry the X-Siftlode-Account header, so the per-tab account rides in the
-  // query string (validated against the browser wallet server-side).
+  // query string (validated against the browser wallet server-side). The account is read once
+  // here: switching accounts always goes through location.reload() (NavSidebar), which rebuilds
+  // this module and reopens the socket, so it's intentionally fixed for the socket's lifetime.
   const account = getActiveAccount();
   const qs = account != null ? `?account=${account}` : "";
   return `${proto}://${location.host}/api/messages/ws${qs}`;
@@ -43,6 +47,9 @@ function open() {
       if (data?.type === "message" && data.message) {
         const e: IncomingMessage = { message: data.message as Message, from: data.from, to: data.to };
         for (const h of handlers) h(e);
+      } else if (data?.type === "unread") {
+        // Sent to a user's OTHER tabs when they read a thread elsewhere, so the badge updates live.
+        for (const h of unreadHandlers) h();
       }
     } catch {
       /* ignore malformed frames */
@@ -87,3 +94,13 @@ export function onMessage(h: Handler): () => void {
     }
   };
 }
+
+// Subscribe to "your unread changed elsewhere" pings (a read on another tab/device). The socket is
+// already opened/closed by onMessage subscribers (the app-wide ChatDock keeps one), so this only
+// registers a callback — it does not open the socket on its own.
+export function onUnread(h: UnreadHandler): () => void {
+  unreadHandlers.add(h);
+  return () => {
+    unreadHandlers.delete(h);
+  };
+}
diff --git a/frontend/src/lib/messaging.ts b/frontend/src/lib/messaging.ts
index ee4e1bd..a532db2 100644
--- a/frontend/src/lib/messaging.ts
+++ b/frontend/src/lib/messaging.ts
@@ -6,6 +6,9 @@ import { isUnlocked, subscribeUnlock } from "./e2ee";
 
 export const SYSTEM_ID = 0; // synthetic "Siftlode" system conversation partner id
 
+// Safety-net poll interval for message queries; live updates arrive over the WebSocket.
+export const POLL_MS = 20000;
+
 // Set-once cache of partner public keys (the server is the directory; keys never change).
 const pubCache = new Map<number, string>();
 export async function partnerPub(partnerId: number): Promise<string> {