feat(watch,themes): transcript en sidebar, seek fiable, player instantane, bande themes repliable

- watch: panneau transcription deplace en tete de sidebar au-dessus de
  A suivre (+ scroll auto a l'ouverture sur mobile)
- seek transcript: seekTo postMessage YouTube (sans rechargement),
  time= Twitch VOD, t= Odysee, start= Rumble (start/dm/pt existants)
- watch: lecteur monte des les parametres de route (embed natif),
  squelettes partiels pendant /details au lieu du plein ecran
- themes-nav: bouton replier/deplier persistant (localStorage),
  barre fine avec theme actif quand repliee, cles i18n FR/EN

src/components/themes/themes-nav.component.ts

@@ -2,12 +2,15 @@ import { ChangeDetectionStrategy, Component, ElementRef, QueryList, ViewChild, V
 import { CommonModule } from '@angular/common';
 import { Router, NavigationEnd, ActivatedRoute } from '@angular/router';
 import { ThemesService } from '../../services/themes.service';
+import { TranslatePipe } from '../../pipes/translate.pipe';
+
+const THEMES_BAR_COLLAPSED_KEY = 'newtube.themesBarCollapsed';
 
 @Component({
   selector: 'app-themes-nav',
   standalone: true,
   changeDetection: ChangeDetectionStrategy.OnPush,
-  imports: [CommonModule],
+  imports: [CommonModule, TranslatePipe],
   templateUrl: './themes-nav.component.html'
 })
 export class ThemesNavComponent implements OnDestroy {
@@ -19,6 +22,26 @@ export class ThemesNavComponent implements OnDestroy {
   activeSlug = this.themesSvc.activeSlug;
   displayedThemes = () => this.themes();
 
+  /** Bande repliée/dépliée (persistée) : la barre reste masquable en permanence. */
+  collapsed = signal<boolean>((() => {
+    try { return localStorage.getItem(THEMES_BAR_COLLAPSED_KEY) === '1'; } catch { return false; }
+  })());
+
+  toggleCollapsed(): void {
+    const next = !this.collapsed();
+    this.collapsed.set(next);
+    try { localStorage.setItem(THEMES_BAR_COLLAPSED_KEY, next ? '1' : '0'); } catch {}
+  }
+
+  activeThemeLabel(): string {
+    try {
+      const slug = this.activeSlug();
+      const found = this.themes().find((t) => t.slug === slug);
+      if (found) return this.themesSvc.i18nLabel(found);
+    } catch {}
+    return '';
+  }
+
   @ViewChildren('pill', { read: ElementRef }) pills!: QueryList<ElementRef<HTMLButtonElement>>;
   @ViewChild('scroll', { static: false }) scrollRef?: ElementRef<HTMLDivElement>;