feat(channel): identite chaine partagee cliquable partout + logos fiabilises

- Nouveau app-channel-identity (avatar+nom -> /channel, fallback resolve /api/channels, initiales sinon)
- ProviderBadge: accepte les ids courts yt/dm/tw/pt/od/ru
- Search adapters yt/dm/pt/od: conservent channelExternalId/channelAvatarUrl (pt derive instance|channel)
- video-card/themes/watch/related/suggestions/subscriptions/channel-header uniformises sur l'identite partagee

src/components/themes/theme-page.component.ts

@@ -8,6 +8,7 @@ import { Video } from '../../models/video.model';
 import { TranslatePipe } from '../../pipes/translate.pipe';
 import { LikeButtonComponent } from '../shared/components/like-button/like-button.component';
 import { ProviderBadgeComponent } from '../../app/shared/components/provider-badge/provider-badge.component';
+import { ChannelIdentityComponent } from '../../app/shared/components/channel-identity/channel-identity.component';
 import { DurationPipe } from '../../app/shared/pipes/duration.pipe';
 import { classifyVideo, isShortVideo } from '../../app/shared/utils/video-kind';
 
@@ -24,7 +25,7 @@ interface ProviderBlock {
   standalone: true,
   changeDetection: ChangeDetectionStrategy.OnPush,
   templateUrl: './theme-page.component.html',
-  imports: [CommonModule, RouterLink, TranslatePipe, LikeButtonComponent, ProviderBadgeComponent, DurationPipe]
+  imports: [CommonModule, RouterLink, TranslatePipe, LikeButtonComponent, ProviderBadgeComponent, DurationPipe, ChannelIdentityComponent]
 })
 export class ThemePageComponent {
   private route = inject(ActivatedRoute);