Merge feature/s3b-deurl-filter-state: de-URL filter state + share-view link

S3b:
- refactor(filters): stop mirroring filters to the URL; localStorage canonical
- feat(filters): opt-in "Share view" link button (filters/sort/scope)

frontend/src/App.tsx

@@ -10,7 +10,7 @@ import {
   saveLocalTheme,
   type ThemePrefs,
 } from "./lib/theme";
-import { hasFilterParams, paramsToFilters, readPage, syncUrl, type Page } from "./lib/urlState";
+import { hasFilterParams, paramsToFilters, readPage, stripUrlParams, type Page } from "./lib/urlState";
 import {
   loadLayout,
   normalizeLayout,
@@ -85,12 +85,10 @@ export default function App() {
   function setFilters(next: FeedFilters) {
     setFiltersState(next);
     localStorage.setItem(FILTERS_KEY, JSON.stringify(next));
-    syncUrl(next, page);
   }
 
   function setPage(next: Page) {
     setPageState(next);
-    syncUrl(filters, next);
   }
 
   function setSidebarLayout(next: SidebarLayout) {
@@ -101,8 +99,16 @@ export default function App() {
 
   useEffect(() => applyTheme(theme), [theme]);
 
-  // Reflect the initial filters + page into the address bar so the URL is always shareable.
-  useEffect(() => syncUrl(filters, page), []); // eslint-disable-line react-hooks/exhaustive-deps
+  // Filters live in localStorage, not the address bar. If we arrived via a "Share view"
+  // link, its params have already hydrated the initial state — persist them and strip the
+  // query so the URL stays clean from here on.
+  useEffect(() => {
+    const params = new URLSearchParams(window.location.search);
+    if (hasFilterParams(params) || params.has("page")) {
+      localStorage.setItem(FILTERS_KEY, JSON.stringify(filters));
+      stripUrlParams();
+    }
+  }, []); // eslint-disable-line react-hooks/exhaustive-deps
 
   const meQuery = useQuery({ queryKey: ["me"], queryFn: api.me });
 

frontend/src/components/Sidebar.tsx

@@ -10,6 +10,7 @@ import {
   Pencil,
   RefreshCw,
   RotateCcw,
+  Share2,
   X,
 } from "lucide-react";
 import {
@@ -33,6 +34,8 @@ import {
   type SidebarLayout,
   type WidgetId,
 } from "../lib/sidebarLayout";
+import { shareUrl } from "../lib/urlState";
+import { notify } from "../lib/notifications";
 
 // Filter ids; display labels resolved at render time via t("sidebar.sort.<id>") etc.
 const SORT_IDS = [
@@ -196,6 +199,15 @@ export default function Sidebar({
     (dateActive ? 1 : 0);
   const active = activeCount > 0;
 
+  async function shareView() {
+    try {
+      await navigator.clipboard.writeText(shareUrl(filters));
+      notify({ message: t("sidebar.shareCopied") });
+    } catch {
+      notify({ level: "warning", message: t("sidebar.shareFailed") });
+    }
+  }
+
   function clearAll() {
     setCustomDates(false);
     setFilters({ ...DEFAULT_SIDEBAR_FILTERS, q: filters.q, scope: filters.scope });
@@ -486,6 +498,16 @@ export default function Sidebar({
               {t("sidebar.clearAll")}
             </button>
           )}
+          {!editing && (
+            <button
+              onClick={shareView}
+              title={t("sidebar.shareView")}
+              aria-label={t("sidebar.shareView")}
+              className="p-1.5 rounded-lg text-muted hover:text-fg hover:bg-card transition"
+            >
+              <Share2 className="w-4 h-4" />
+            </button>
+          )}
           {editing && (
             <button
               onClick={() => setLayout({ ...DEFAULT_LAYOUT })}

frontend/src/i18n/locales/de/sidebar.json

@@ -26,6 +26,9 @@
   "clearDates": "Daten löschen",
   "reshuffle": "Neu mischen",
   "noMatchingTags": "Keine passenden Tags",
+  "shareView": "Link zu dieser Ansicht kopieren",
+  "shareCopied": "Ansichts-Link in die Zwischenablage kopiert",
+  "shareFailed": "Link konnte nicht kopiert werden",
   "widget": {
     "show": "Anzeigen",
     "sort": "Sortierung",

frontend/src/i18n/locales/en/sidebar.json

@@ -26,6 +26,9 @@
   "clearDates": "clear dates",
   "reshuffle": "Reshuffle",
   "noMatchingTags": "No matching tags here",
+  "shareView": "Copy a link to this view",
+  "shareCopied": "View link copied to clipboard",
+  "shareFailed": "Couldn't copy the link",
   "widget": {
     "show": "Show",
     "sort": "Sort",

frontend/src/i18n/locales/hu/sidebar.json

@@ -26,6 +26,9 @@
   "clearDates": "dátumok törlése",
   "reshuffle": "Újrakeverés",
   "noMatchingTags": "Nincs ide illő címke",
+  "shareView": "Hivatkozás másolása erre a nézetre",
+  "shareCopied": "Nézet-hivatkozás a vágólapra másolva",
+  "shareFailed": "Nem sikerült a hivatkozás másolása",
   "widget": {
     "show": "Megjelenítés",
     "sort": "Rendezés",

frontend/src/lib/urlState.ts

@@ -1,12 +1,14 @@
-// Serialize feed filters to/from a compact, human-readable URL query string, so a
-// pasted URL reproduces exactly what's on screen (handy for "here's the URL, I see
-// this bug"). Only non-default values are emitted to keep URLs clean.
+// Serialize feed filters to/from a compact, human-readable URL query string. Filters are
+// NOT kept in the address bar during normal use (localStorage is the single source of
+// truth); this serializer powers the explicit "Share view" link and the one-time hydration
+// when someone opens such a link. Only non-default values are emitted to keep URLs clean.
 import type { FeedFilters } from "./api";
 
 const KEYS = [
   "q",
   "show",
   "sort",
+  "scope",
   "normal",
   "shorts",
   "live",
@@ -25,6 +27,7 @@ export function filtersToParams(f: FeedFilters): URLSearchParams {
   if (f.q) p.set("q", f.q);
   if (f.show && f.show !== "unwatched") p.set("show", f.show);
   if (f.sort && f.sort !== "newest") p.set("sort", f.sort);
+  if (f.scope === "all") p.set("scope", "all");
   if (!f.includeNormal) p.set("normal", "0");
   if (f.includeShorts) p.set("shorts", "1");
   if (f.includeLive) p.set("live", "1");
@@ -51,6 +54,7 @@ export function paramsToFilters(params: URLSearchParams, base: FeedFilters): Fee
   if (params.has("q")) f.q = params.get("q") ?? "";
   if (params.has("show")) f.show = params.get("show") || "unwatched";
   if (params.has("sort")) f.sort = params.get("sort") || "newest";
+  if (params.has("scope")) f.scope = params.get("scope") === "all" ? "all" : "my";
   if (params.has("normal")) f.includeNormal = params.get("normal") !== "0";
   if (params.has("shorts")) f.includeShorts = params.get("shorts") === "1";
   if (params.has("live")) f.includeLive = params.get("live") === "1";
@@ -81,11 +85,19 @@ export function readPage(): Page {
   return p === "channels" || p === "stats" ? p : "feed";
 }
 
-/** Reflect the current filters + page into the address bar without adding history entries. */
-export function syncUrl(f: FeedFilters, page: Page = "feed"): void {
+/** Build a shareable absolute URL that reproduces the current filters (+ page). Used by the
+ * opt-in "Share view" action — filters are not otherwise written to the address bar. */
+export function shareUrl(f: FeedFilters, page: Page = "feed"): string {
   const params = filtersToParams(f);
   if (page !== "feed") params.set("page", page);
   const qs = params.toString();
-  const url = qs ? `${window.location.pathname}?${qs}` : window.location.pathname;
-  window.history.replaceState(null, "", url);
+  return `${window.location.origin}${window.location.pathname}${qs ? `?${qs}` : ""}`;
+}
+
+/** Strip any filter/page query params from the address bar (after hydrating from a share
+ * link), leaving a clean URL without touching history. */
+export function stripUrlParams(): void {
+  if (window.location.search) {
+    window.history.replaceState(null, "", window.location.pathname);
+  }
 }