Fix username resolver: use www.reddit.com, not api.reddit.com

api.reddit.com/api/user_data_by_account_ids returns 404 without an
OAuth token — which is why every chat in the dashboard sat on
t2_xxx or unknown. The same path on www.reddit.com (with a .json
suffix) is served unauthenticated and returns the expected user
map. Switch the resolver to that host so enrichUsernames actually
succeeds.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/services/chat/service.ts

@@ -1066,7 +1066,8 @@ export class ChatService {
       }
     }
 
-    // Pass 3 — for every chat still on a raw t2 ID, call the resolver.
+    // Pass 3 — for every chat still on a raw t2 ID, batch-resolve via the
+    // injected resolver (www.reddit.com/api/user_data_by_account_ids.json).
     const needed: string[] = [];
     for (const chat of this.cache.get()) {
       const t2 = this.extractT2(chat);
@@ -1078,6 +1079,7 @@ export class ChatService {
         let updated = 0;
         for (const [t2, name] of Object.entries(got)) {
           const bare = t2.replace(/^t2_/, '');
+          if (!name) continue;
           this.t2ToUsername.set(bare, name);
           this.persistUsername(t2, name);
           for (const chat of this.cache.get()) {