feat(settings): cross-tab fuzzy search + tab restructure polish (#263)

Cross-tab settings search:
- Static SETTINGS_INDEX covering every sub-section of every tab, with
  free-form keywords per entry so "scrobble" finds Last.fm, "replay gain"
  finds Playback, etc.
- matchScore() does substring-first ranking, falls back to a char-in-order
  fuzzy match so typos still yield hits.
- Active tab keeps its in-place hide/show filter; matches from other tabs
  render at the top as a clickable "In other tabs" list (tab badge +
  sub-section title). Clicking clears the query, switches tab, and scrolls
  + opens the target sub-section.
- All 8 locales updated: new searchOtherTabs key, searchNoResults reworded
  (old "try another tab" hint is now handled by the list itself).

Settings restructure polish:
- "Next Track Buffering" moved from Audio to the Storage tab — sits
  between Offline Library and Downloads.
- Storage tab label renamed across 8 locales: "Storage & Downloads" →
  "Offline & Cache" (equivalents per locale). nb locale was missing
  tabStorage entirely; added. Tab id stays 'storage' to avoid breaking
  persisted state.
- Library tab: Random Mix sub-section now opens by default (previously
  both sub-sections started collapsed) and is renamed "Random Mix
  Blacklist" in all 8 locales — the section is entirely a blacklist
  config, the old title was misleading.
- Lyrics tab:
  * Standard / YouLyPlus rows use the same toggle style as the "Show
    lyrics as static text" row and stack vertically. Order swapped so
    YouLyPlus is first.
  * Provider list (Server / LRCLIB / Netease) moved to appear directly
    under the Standard toggle as its sub-item, indented, instead of after
    the static-text toggle.
  * Classic / Apple Music-like rows likewise rebuilt as vertical toggle
    rows.
- One pre-existing typo carried in from #261 fixed along the way: the
  openAddServerInvite handler in Settings referenced the renamed tab id
  'server' (pre-#259) — now 'servers'. [Note: already landed in PR #262,
  keeping this commit clean of that.]

Co-authored-by: Psychotoxical <dev@psysonic.app>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/de.ts

@@ -688,7 +688,7 @@ export const deTranslation = {
     aboutContributorsLabel: 'Mitwirkende',
     showChangelogOnUpdate: "'Was ist neu' bei Update anzeigen",
     showChangelogOnUpdateDesc: 'Blendet nach einem Update einen dezenten Changelog-Banner über Now Playing ein. Klick öffnet die Release Notes, X blendet ihn aus.',
-    randomMixTitle: 'Zufallsmix',
+    randomMixTitle: 'Zufallsmix-Blacklist',
     randomMixBlacklistTitle: 'Eigene Filter-Keywords',
     randomMixBlacklistDesc: 'Songs werden ausgeschlossen, wenn ein Keyword auf Genre, Titel, Album oder Künstler zutrifft (aktiv wenn die Checkbox oben an ist).',
     randomMixBlacklistPlaceholder: 'Keyword hinzufügen…',
@@ -696,7 +696,7 @@ export const deTranslation = {
     randomMixBlacklistEmpty: 'Noch keine eigenen Keywords hinzugefügt.',
     randomMixHardcodedTitle: 'Eingebaute Keywords (aktiv wenn Checkbox an)',
     tabAudio: 'Audio',
-    tabStorage: 'Speicher & Downloads',
+    tabStorage: 'Offline & Cache',
     tabAppearance: 'Darstellung',
     tabLibrary: 'Bibliothek',
     tabServers: 'Server',
@@ -707,7 +707,8 @@ export const deTranslation = {
     aboutContributorsCount_one: '{{count}} Beitrag',
     aboutContributorsCount_other: '{{count}} Beiträge',
     searchPlaceholder: 'Einstellungen durchsuchen…',
-    searchNoResults: 'Keine passenden Einstellungen in diesem Tab. Probier einen anderen.',
+    searchNoResults: 'Keine Treffer für deine Suche.',
+    searchOtherTabs: 'In anderen Tabs',
     integrationsPrivacyTitle: 'Hinweis zum Datenschutz',
     integrationsPrivacyBody: 'Alle Integrationen auf diesem Tab sind <strong>Opt-in</strong> und senden, sobald aktiviert, Daten an externe Dienste oder an deinen Navidrome-Server. Last.fm erhält deinen Wiedergabeverlauf, Discord zeigt den aktuell laufenden Track in deinem Profil an, Bandsintown wird pro Künstler für Tour-Daten abgefragt, und der „Jetzt läuft"-Hinweis veröffentlicht deinen aktuellen Titel für andere Benutzer deines Navidrome-Servers. Wer das nicht möchte, lässt den jeweiligen Abschnitt einfach deaktiviert.',
     homeCustomizerTitle: 'Startseite',