fix(privacy): sanitize console error/warn to prevent PII leakage

Replace raw error object logging (which may contain Matrix event
payloads, user IDs, or message bodies) with e.message-only strings
in three files:
- CallEmbed.ts: state update and event widget feed errors
- msgContent.ts: image/video element load failures and thumb errors
- RoomInput.tsx: GIF send failure

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/plugins/call/CallEmbed.ts

@@ -390,7 +390,7 @@ export class CallEmbed {
     if (this.call === null) return;
     const raw = ev.getEffectiveEvent();
     this.call.feedStateUpdate(raw as IRoomEvent).catch((e) => {
-      console.error('Error sending state update to widget: ', e);
+      console.error('Error sending state update to widget:', e instanceof Error ? e.message : 'unknown error');
     });
   }
 
@@ -496,7 +496,7 @@ export class CallEmbed {
       } else {
         const raw = ev.getEffectiveEvent();
         this.call.feedEvent(raw as IRoomEvent).catch((e) => {
-          console.error('Error sending event to widget: ', e);
+          console.error('Error sending event to widget:', e instanceof Error ? e.message : 'unknown error');
         });
       }
     }