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/app/search/adapters/pt.ts

@@ -12,16 +12,26 @@ export class PtAdapter implements ProviderAdapter<VideoItem> {
     if (params.pageToken) httpParams = httpParams.set('page', params.pageToken);
     if (params.sort) httpParams = httpParams.set('sort', params.sort);
     const res = await firstValueFrom(this.http.get<any>(`/api/search`, { params: httpParams }));
-    const items: VideoItem[] = (res?.groups?.pt || []).map((it: any) => ({
-      id: it.id,
-      provider: 'peertube',
-      title: it.title,
-      channelName: it.uploaderName,
-      durationSec: it.duration,
-      thumbnailUrl: it.thumbnail,
-      viewCount: undefined,
-      publishedAt: undefined,
-    }));
+    const items: VideoItem[] = (res?.groups?.pt || []).map((it: any) => {
+      // PeerTube identifie une chaîne par `instance|channel` : l'instance est
+      // dérivée de l'URL vidéo, le nom de chaîne de `channelId`.
+      let channelExternalId: string | undefined;
+      try {
+        const host = it?.url ? new URL(String(it.url)).hostname : '';
+        if (host && it?.channelId) channelExternalId = `${host}|${it.channelId}`;
+      } catch {}
+      return {
+        id: it.id,
+        provider: 'peertube',
+        title: it.title,
+        channelName: it.uploaderName,
+        durationSec: it.duration,
+        thumbnailUrl: it.thumbnail,
+        viewCount: undefined,
+        publishedAt: undefined,
+        channelExternalId,
+      };
+    });
     return { items, total: Array.isArray(res?.groups?.pt) ? res.groups.pt.length : 0 };
   }
 }