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/bootstrap.ts

@@ -208,7 +208,9 @@ export async function bootstrap(config: Config, logger: Logger): Promise<AppCont
         const chunk = ids.slice(i, i + 100).join(',');
         try {
           const res = await fetchWithTimeout(
-            `https://api.reddit.com/api/user_data_by_account_ids?ids=${encodeURIComponent(chunk)}`,
+            // www.reddit.com serves this unauthenticated; the api.reddit.com
+            // host 404s the same path without an OAuth token.
+            `https://www.reddit.com/api/user_data_by_account_ids.json?ids=${encodeURIComponent(chunk)}`,
             { headers: { 'User-Agent': config.reddit.userAgent }, timeoutMs: 15_000 },
           );
           if (!res.ok) {