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/styles/components.css

@@ -2605,6 +2605,66 @@
   text-align: center;
 }
 
+.settings-search-other-tabs {
+  margin-top: var(--space-4);
+  margin-bottom: var(--space-6);
+  padding: var(--space-3);
+  border-radius: var(--radius-md);
+  background: var(--bg-card);
+  border: 1px solid var(--border-subtle);
+}
+.settings-search-other-tabs-title {
+  font-size: 12px;
+  font-weight: 600;
+  text-transform: uppercase;
+  letter-spacing: 0.04em;
+  color: var(--text-muted);
+  margin-bottom: var(--space-2);
+}
+.settings-search-other-tabs-list {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+}
+.settings-search-other-tab-item {
+  width: 100%;
+  display: flex;
+  align-items: center;
+  gap: var(--space-2);
+  padding: 8px 10px;
+  background: transparent;
+  border: 1px solid transparent;
+  border-radius: var(--radius-sm);
+  color: var(--text-primary);
+  text-align: left;
+  cursor: pointer;
+  font-size: 13px;
+  transition: background 0.12s, border-color 0.12s;
+}
+.settings-search-other-tab-item:hover {
+  background: var(--bg-hover);
+  border-color: var(--border);
+}
+.settings-search-other-tab-badge {
+  flex-shrink: 0;
+  font-size: 11px;
+  font-weight: 500;
+  padding: 2px 8px;
+  border-radius: 999px;
+  background: color-mix(in srgb, var(--accent) 15%, transparent);
+  color: var(--accent);
+}
+.settings-search-other-tab-title {
+  flex: 1;
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 /* ── Mitwirkende: Card-Grid mit klappbaren Beitragslisten ────────────────── */
 .contributors-grid {
   display: grid;