feat(lucky-mix): instant mix from your preferences

Lucky Mix targets ~50 tracks in one run: pick seeds from your most-played artists/albums and 4+ rated songs, add similar tracks, then fill the mix with random library picks, skipping anything you rated 1–2.
On start it trims the old “upcoming” tail so the queue does not show stale next tracks, starts playback on the first viable seed, routes to Now Playing, and can emit structured steps to the backend debug log.

src/locales/en.ts

@@ -32,6 +32,7 @@ export const enTranslation = {
     expandPlaylists: 'Expand playlists',
     collapsePlaylists: 'Collapse playlists',
     more: 'More',
+    feelingLucky: 'Lucky Mix',
   },
   home: {
     hero: 'Featured',
@@ -284,6 +285,8 @@ export const enTranslation = {
     mixByTracksDesc: 'Random selection of tracks from your entire library',
     mixByAlbums: 'Mix by Albums',
     mixByAlbumsDesc: 'Random album picks for your next discovery',
+    mixByLucky: 'Lucky Mix',
+    mixByLuckyDesc: 'Smart instant mix from your top artists, albums, and ratings',
   },
   randomAlbums: {
     title: 'Random Albums',
@@ -336,6 +339,11 @@ export const enTranslation = {
     filterPanelDesc: 'Click a genre tag or artist name in the tracklist below to block it from future mixes.',
     genreClickHint: 'Click a genre tag to add it\nas a filter keyword.\nMatches genre, title, album & artist.',
   },
+  luckyMix: {
+    done: 'Lucky mix ready: {{count}} tracks',
+    failed: 'Could not build lucky mix. Try again.',
+    unavailable: 'Lucky Mix is unavailable for this server.',
+  },
   albums: {
     title: 'All Albums',
     sortByName: 'A–Z (Album)',
@@ -722,6 +730,8 @@ export const enTranslation = {
     showChangelogOnUpdate: "Show 'What's New' on update",
     showChangelogOnUpdateDesc: "Show a discreet changelog banner above Now Playing after an update. Click opens the release notes; X dismisses it.",
     randomMixTitle: 'Random Mix Blacklist',
+    luckyMixMenuTitle: 'Show Lucky Mix in menu',
+    luckyMixMenuDesc: 'Enables Lucky Mix in Build a Mix and as a separate menu item when split navigation is on. Visible only when AudioMuse is enabled on the active server.',
     randomMixBlacklistTitle: 'Custom Filter Keywords',
     randomMixBlacklistDesc: 'Songs are excluded when any keyword matches their genre, title, album, or artist (active when the checkbox above is on).',
     randomMixBlacklistPlaceholder: 'Add keyword…',
@@ -757,7 +767,7 @@ export const enTranslation = {
     sidebarDrag: 'Drag to reorder',
     sidebarFixed: 'Always visible',
     randomNavSplitTitle: 'Split Mix navigation',
-    randomNavSplitDesc: 'Show "Random Mix" and "Random Albums" as separate sidebar entries instead of the "Build a Mix" hub.',
+    randomNavSplitDesc: 'Show "Random Mix", "Random Albums", and "Lucky Mix" as separate sidebar entries instead of the "Build a Mix" hub.',
     tabInput: 'Input',
     tabUsers: 'Users',
     tabSystem: 'System',