feat(i18n): translate remaining components (HU/EN/DE)

Feed, VideoCard, Sidebar, PlayerModal, Channels, Stats, SettingsPanel,
OnboardingWizard, NotificationCenter, Toaster, ErrorBoundary and the relativeTime
helper are now fully translated in Hungarian, English and German, each with its own
locale area file (auto-loaded). Key parity verified across all three languages.

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

@@ -0,0 +1,17 @@
+{
+  "watchedUnmark": "Watched — click to unmark",
+  "markWatched": "Mark watched",
+  "savedRemove": "Saved — click to remove",
+  "saveForLater": "Save for later",
+  "unhide": "Unhide",
+  "hide": "Hide",
+  "onlyThisChannel": "Only this channel",
+  "thisChannel": "This channel",
+  "continueTitle": "Continue where you left off",
+  "continue": "Continue",
+  "restartTitle": "Play from the beginning",
+  "restart": "Restart",
+  "play": "Play",
+  "stream": "stream",
+  "views": "views"
+}

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

@@ -0,0 +1,69 @@
+{
+  "intro": "Set a channel's <0>priority</0> to push its videos up when you sort by “Channel priority”, attach your own <1>tags</1> to filter the feed, or <2>hide</2> a channel to drop it from the feed without unsubscribing.",
+  "filterPlaceholder": "Filter channels…",
+  "syncSubscriptions": "Sync subscriptions",
+  "syncSubscriptionsHint": "Re-import your subscription list from YouTube — adds channels you've newly followed and drops ones you've unfollowed. The videos themselves keep syncing automatically in the background; this does not re-fetch them.",
+  "backfillEverything": "Backfill everything",
+  "backfillEverythingHint": "Request full back-catalog backfill for every channel you're subscribed to. Older videos and search become complete as the shared daily quota allows — this can take a while.",
+  "filters": {
+    "all": "All",
+    "needsFull": "Needs full history",
+    "fullySynced": "Fully synced",
+    "hidden": "Hidden"
+  },
+  "tags": {
+    "yourTags": "Your tags",
+    "yourTagsHint": "Your personal labels. Attach them to channels below, then filter the feed by tag from the sidebar. (Separate from the automatic language/topic tags.)",
+    "newTag": "new tag",
+    "createTag": "Create tag"
+  },
+  "loading": "Loading channels…",
+  "empty": "No channels.",
+  "stats": {
+    "channels": "Channels",
+    "channelsHint": "Channels you're subscribed to.",
+    "recentSynced": "Recent synced",
+    "recentSyncedHint": "Channels whose recent uploads are in the local DB and show in your feed.",
+    "fullHistory": "Full history",
+    "fullHistoryHint": "Channels whose entire back-catalog is fetched, out of the ones you've requested full history for.",
+    "left": "left",
+    "leftHint": "Rough estimate to finish full-history backfill of {{count}} pending channel(s), based on the shared daily quota.",
+    "myVideos": "My videos",
+    "myVideosHint": "Total videos available across your channels.",
+    "quotaLeft": "Quota left",
+    "quotaLeftHint": "Shared YouTube API budget left today (resets midnight US Pacific)."
+  },
+  "row": {
+    "stored": "{{formatted}} stored",
+    "subs": "{{formatted}} subs",
+    "priorityHint": "Your ranking for this channel. Sort the feed by “Channel priority” to bring higher-priority channels to the top.",
+    "raisePriority": "Raise priority",
+    "lowerPriority": "Lower priority",
+    "recent": "recent",
+    "recentSyncedHint": "Recent uploads synced.",
+    "recentNotSyncedHint": "Recent uploads not fetched yet.",
+    "full": "full",
+    "fullHint": "Full history fetched.",
+    "fullHistoryQueued": "full history queued",
+    "queuedRequestedHint": "Full history requested — this channel's whole back-catalog will backfill as the shared quota allows. Click to cancel your request.",
+    "queuedByOtherHint": "Another subscriber already requested this channel's full history, so its whole back-catalog is on its way to everyone — nothing to do here.",
+    "getFullHistory": "get full history",
+    "getFullHistoryHint": "Only recent uploads so far. Click to request this channel's full back-catalog (older videos + complete search).",
+    "hiddenHint": "Hidden — this channel's videos are kept out of your feed. Click to show them again.",
+    "hideHint": "Hide this channel's videos from your feed. It stays subscribed; this doesn't unsubscribe on YouTube.",
+    "unhide": "Unhide",
+    "hideFromFeed": "Hide from feed",
+    "unsubscribeHint": "Unsubscribe from this channel on YouTube (changes your real account). Read-only mode hides this — use Hide instead.",
+    "unsubscribeOnYoutube": "Unsubscribe on YouTube",
+    "thisChannel": "This channel"
+  },
+  "notify": {
+    "synced": "Synced {{count}} subscriptions",
+    "syncFailed": "Subscription sync failed",
+    "unsubscribed": "Unsubscribed on YouTube",
+    "unsubscribeFailed": "Unsubscribe failed",
+    "fullHistoryRequested": "Full history requested for {{count}} channels",
+    "fullHistoryFailed": "Couldn't request full history"
+  },
+  "confirmUnsubscribe": "Unsubscribe from \"{{name}}\" on YouTube? This changes your real YouTube account. To just remove it from your feed, hide it instead."
+}

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

@@ -0,0 +1,9 @@
+{
+  "boundary": {
+    "title": "Something went wrong.",
+    "subtitle": "The app hit an unexpected error.",
+    "reload": "Reload",
+    "notifTitle": "Something broke",
+    "notifMessage": "Unexpected error"
+  }
+}

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

@@ -0,0 +1,17 @@
+{
+  "loading": "Loading feed…",
+  "loadError": "Couldn't load the feed.",
+  "emptyTitle": "Your feed is empty",
+  "emptyBody": "Connect your YouTube account to import your subscriptions and build your feed.",
+  "setUp": "Set up my feed",
+  "noMatches": "No videos match these filters.",
+  "videoCount_one": "{{formattedCount}} video",
+  "videoCount_other": "{{formattedCount}} videos",
+  "loadingMore": "Loading more…",
+  "hiddenNamed": "Hidden “{{title}}”",
+  "hidden": "Video hidden",
+  "undo": "Undo",
+  "markedWatchedNamed": "Marked watched “{{title}}”",
+  "markedWatched": "Marked watched",
+  "unwatch": "Unwatch"
+}

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

@@ -0,0 +1,19 @@
+{
+  "title": "Notifications",
+  "clearAll": "Clear all",
+  "clear": "Clear",
+  "empty": "No notifications yet.",
+  "actionNeeded": "Action needed",
+  "dismiss": "Dismiss",
+  "findInFeed": "Find in feed",
+  "unhide": "Unhide",
+  "unwatch": "Unwatch",
+  "unhidden": "Unhidden “{{title}}”",
+  "unwatched": "Unwatched “{{title}}”",
+  "time": {
+    "justNow": "just now",
+    "minutes": "{{count}}m ago",
+    "hours": "{{count}}h ago",
+    "days": "{{count}}d ago"
+  }
+}

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

@@ -0,0 +1,29 @@
+{
+  "close": "Close",
+  "consent": "Google will show a <0>\"Google hasn't verified this app\"</0> screen — that's expected, because Siftlode hasn't gone through Google's full review. It's safe to continue: click <1>Advanced</1> → <2>Go to Siftlode</2>. You can revoke access anytime from your <3>Google Account</3>.",
+  "read": {
+    "title": "Connect your YouTube subscriptions",
+    "body": "You're signed in. To build your feed, Siftlode needs <0>read-only</0> access to the channels you're subscribed to on YouTube. It never posts, deletes, or changes anything with this.",
+    "connect": "Connect (read-only)",
+    "skip": "Skip for now"
+  },
+  "importing": {
+    "title": "Building your feed…",
+    "body": "Importing your YouTube subscriptions. Channels already in Siftlode show up instantly; any new ones fill in automatically in the background."
+  },
+  "write": {
+    "title": "You're connected",
+    "importFailed": "Your YouTube account is connected, but importing subscriptions failed — you can retry from Settings → Sync. ",
+    "feedReady": "Your feed is ready{{channels}}. Optionally, let Siftlode ",
+    "feedReadyChannels": " ({{count}} channels)",
+    "rationale": "<0>unsubscribe</0> from channels on YouTube for you — this needs an extra write permission. Skip it to stay read-only; you can always enable it later in Settings.",
+    "retryImport": "Retry import",
+    "enableUnsubscribe": "Enable unsubscribe",
+    "keepReadOnly": "No thanks — keep it read-only"
+  },
+  "done": {
+    "title": "All set",
+    "body": "Read and unsubscribe access are both granted. You can review or revoke either one anytime in Settings → Account, or from your Google Account.",
+    "done": "Done"
+  }
+}

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

@@ -0,0 +1,17 @@
+{
+  "loading": "Loading…",
+  "backToOriginal": "Back to the original video",
+  "back": "Back",
+  "close": "Close",
+  "closeEsc": "Close (Esc)",
+  "description": "Description",
+  "noDescription": "No description.",
+  "channel": "Channel",
+  "views": "{{formattedCount}} views",
+  "stream": "stream",
+  "watched": "Watched",
+  "markWatched": "Mark watched",
+  "watchedUnmark": "Watched — click to unmark",
+  "jumpToTime": "Jump to this time",
+  "playInApp": "Play in the in-app player"
+}

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

@@ -0,0 +1,101 @@
+{
+  "title": "Settings",
+  "tabs": {
+    "appearance": "Appearance",
+    "notifications": "Notifications",
+    "sync": "Sync",
+    "account": "Account"
+  },
+  "appearance": {
+    "colorScheme": "Color scheme",
+    "display": "Display",
+    "darkMode": "Dark mode",
+    "listView": "List view",
+    "listViewHint": "Show the feed as a compact list instead of a grid of cards.",
+    "performanceMode": "Performance mode",
+    "performanceModeHint": "Turns off the translucent glass blur and soft shadows for snappier rendering on slower machines.",
+    "showHints": "Show hints",
+    "showHintsHint": "These little hover explanations. Turn them off once you know your way around.",
+    "textSize": "Text size"
+  },
+  "notifications": {
+    "title": "Notifications",
+    "sound": "Sound on alerts",
+    "soundHint": "Play a short tone when a notification needs your attention (e.g. errors, prompts).",
+    "autoDismiss": "Auto-dismiss toasts",
+    "autoDismissHint": "When off, pop-up toasts stay until you close them. When on, they fade after the set time.",
+    "dismissAfter": "Dismiss after",
+    "sendTest": "Send a test notification",
+    "testTitle": "Test notification",
+    "testMessage": "This is what a notification looks like."
+  },
+  "sync": {
+    "myStatus": "My sync status",
+    "channels": "Channels",
+    "channelsHint": "How many channels you're subscribed to.",
+    "recentSynced": "Recent synced",
+    "recentSyncedHint": "Channels whose recent uploads (~last year) are already in the local database, so they show in your feed.",
+    "fullHistory": "Full history",
+    "fullHistoryHint": "Channels whose entire back-catalog has been fetched, out of the ones you've requested full history for (opt in per channel on the Channels page).",
+    "fullHistoryEta": "Full history ETA",
+    "fullHistoryEtaHint": "Rough estimate to finish full-history backfill of {{count}} pending channel(s), based on the shared daily quota.",
+    "myVideos": "My videos",
+    "myVideosHint": "Total videos available to you across your subscribed channels.",
+    "quotaLeft": "Quota left today",
+    "quotaLeftHint": "Shared YouTube API budget remaining today (resets midnight US Pacific). Backfill yields to it.",
+    "loading": "Loading…",
+    "apiUsage": "Your API usage",
+    "today": "Today",
+    "todayHint": "YouTube API units your own actions used today (resets midnight US Pacific). Background sync isn't counted here.",
+    "last7d": "Last 7 days",
+    "last30d": "Last 30 days",
+    "allTime": "All time",
+    "byAction": "By action (30d)",
+    "noUsage": "No usage yet.",
+    "actions": "Actions",
+    "syncSubscriptions": "Sync subscriptions",
+    "syncSubscriptionsHint": "Re-import your YouTube subscriptions and pull in any newly-followed channels.",
+    "backfillEverything": "Backfill everything",
+    "backfillEverythingHint": "Request full back-catalog backfill for every channel you're subscribed to. Older videos + complete search fill in as the shared daily quota allows.",
+    "synced": "Synced {{count}} subscriptions",
+    "syncFailed": "Sync failed",
+    "fullHistoryRequested": "Full history requested for {{count}} channels",
+    "fullHistoryFailed": "Couldn't request full history",
+    "admin": "Admin",
+    "adminPauseHint": "Pause or resume the background sync for the whole app (all users).",
+    "resumeBackgroundSync": "Resume background sync",
+    "pauseBackgroundSync": "Pause background sync"
+  },
+  "account": {
+    "title": "Account",
+    "youtubeAccess": "YouTube access",
+    "youtubeAccessIntro": "Sign-in only shares your name and email. YouTube access is granted separately, below — each is optional and revocable anytime in your Google Account.",
+    "readTitle": "Read subscriptions (your feed)",
+    "readGrantedHint": "Granted. Siftlode reads the channels you follow to build your feed. It never changes your YouTube account with this.",
+    "readEnableHint": "Read-only access to your subscriptions — required to build your feed. Siftlode can't modify anything with it.",
+    "writeTitle": "Unsubscribe (write)",
+    "writeGrantedHint": "Granted. You can unsubscribe from channels on YouTube from inside Siftlode. It only writes when you ask it to.",
+    "writeEnableHint": "Lets Siftlode unsubscribe from channels on YouTube for you. Optional — skip it to stay read-only.",
+    "granted": "Granted",
+    "enable": "Enable",
+    "enableHint": "Redirects to Google to grant the permission. Google shows an 'unverified app' notice — that's expected; click Advanced → Go to Siftlode.",
+    "walkMeThrough": "Walk me through setup"
+  },
+  "invites": {
+    "title": "Access requests",
+    "noPending": "No pending requests.",
+    "addPlaceholder": "Add an email directly…",
+    "add": "Add",
+    "decided": "{{count}} decided",
+    "approved": "Approved — they can sign in now",
+    "approveFailed": "Approve failed",
+    "denyFailed": "Deny failed",
+    "addedToWhitelist": "Added to the whitelist",
+    "addFailed": "Couldn't add that email",
+    "requested": "requested {{time}}",
+    "approveHint": "Approve — whitelist this email and email them they're in.",
+    "approve": "Approve",
+    "denyHint": "Deny this request.",
+    "deny": "Deny"
+  }
+}

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

@@ -0,0 +1,65 @@
+{
+  "filters": "Filters",
+  "activeCount": "{{count}} active",
+  "clearAll": "Clear all",
+  "resetDefaults": "Reset to defaults",
+  "customize": "Customize sidebar",
+  "done": "Done",
+  "editHint": "Drag to reorder · eye to show/hide",
+  "channel": "Channel",
+  "loading": "Loading…",
+  "thisChannel": "This channel",
+  "channelCount": "{{count}} channel",
+  "channelCount_other": "{{count}} channels",
+  "dragToReorder": "Drag to reorder",
+  "showWidget": "Show widget",
+  "hideWidget": "Hide widget",
+  "expand": "Expand",
+  "collapse": "Collapse",
+  "any": "Any",
+  "all": "All",
+  "tagModeTooltip": "Match any vs all selected tags",
+  "custom": "Custom",
+  "from": "From",
+  "to": "To",
+  "clearDates": "clear dates",
+  "widget": {
+    "show": "Show",
+    "sort": "Sort",
+    "date": "Upload date",
+    "content": "Content type",
+    "language": "Language",
+    "topic": "Topic"
+  },
+  "show": {
+    "unwatched": "Unwatched",
+    "in_progress": "In progress",
+    "all": "All",
+    "watched": "Watched",
+    "saved": "Saved",
+    "hidden": "Hidden"
+  },
+  "sort": {
+    "newest": "Newest",
+    "oldest": "Oldest",
+    "views": "Most viewed",
+    "duration_desc": "Longest",
+    "duration_asc": "Shortest",
+    "title": "Name (A–Z)",
+    "subscribers": "Channel subscribers",
+    "priority": "Channel priority",
+    "shuffle": "Surprise me"
+  },
+  "content": {
+    "normal": "Normal",
+    "shorts": "Shorts",
+    "live": "Live / Upcoming"
+  },
+  "datePreset": {
+    "24h": "24h",
+    "1week": "1 week",
+    "1month": "1 month",
+    "6months": "6 months",
+    "1year": "1 year"
+  }
+}

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

@@ -0,0 +1,13 @@
+{
+  "title": "API quota usage",
+  "rangeDays": "{{count}}d",
+  "introBefore": "YouTube Data API units attributed by who triggered the spend. ",
+  "introSystem": "System",
+  "introAfter": " is shared background work (scheduled backfill, enrichment, resync) that isn't tied to one person.",
+  "loading": "Loading…",
+  "noData": "No data.",
+  "dailyTotal": "Daily total ({{count}}d · {{units}} units)",
+  "noUsageInRange": "No usage in this range.",
+  "dailyTooltip": "{{day}}: {{units}} units",
+  "system": "System (background)"
+}

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

@@ -0,0 +1,10 @@
+{
+  "justNow": "just now",
+  "secondsAgo": "{{count}}s ago",
+  "minutesAgo": "{{count}} min ago",
+  "hoursAgo": "{{count}}h ago",
+  "daysAgo": "{{count}}d ago",
+  "weeksAgo": "{{count}} wk ago",
+  "monthsAgo": "{{count}} mo ago",
+  "yearsAgo": "{{count}} yr ago"
+}