Don't crash bootstrap on Matrix token capture failure

If chat.reddit.com sniffing fails, fall through with a placeholder
credential set so the post-monitoring/processor side of the bot
(and the web UI) stay up. Chat features are disabled until the
next successful token refresh.

Also dump diagnostics on sniff timeout: final page URL, every host
the page touched (with request counts + whether any carried an
Authorization header), and a full-page screenshot to data/matrix-debug.png.
This makes the three failure modes (page didn't load / loaded but
never hit Matrix / hit Matrix without auth) distinguishable from logs.

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

src/services/chat/matrix/token-extractor.ts

@@ -66,15 +66,25 @@ export async function extractMatrixCredentials(
     });
 
     let done = false;
+    // Track every host the page touches so we can tell, on timeout, whether
+    // chat.reddit.com failed to load at all, loaded but never reached the
+    // Matrix homeserver, or reached it but without a bearer header.
+    const seenHosts = new Map<string, { count: number; sawAuth: boolean }>();
     const onRequest = (request: import('playwright').Request) => {
       if (done) return;
       try {
         const url = new URL(request.url());
-        if (!MATRIX_HOST_RE.test(url.hostname)) return;
+        const isMatrix = MATRIX_HOST_RE.test(url.hostname);
         const headers = request.headers();
         const auth = headers['authorization'] || headers['Authorization'];
-        if (!auth || !auth.toLowerCase().startsWith('bearer ')) return;
-        const token = auth.slice('bearer '.length).trim();
+        const hasAuth = !!auth && auth.toLowerCase().startsWith('bearer ');
+        const entry = seenHosts.get(url.hostname) ?? { count: 0, sawAuth: false };
+        entry.count += 1;
+        if (hasAuth) entry.sawAuth = true;
+        seenHosts.set(url.hostname, entry);
+        if (!isMatrix) return;
+        if (!hasAuth) return;
+        const token = auth!.slice('bearer '.length).trim();
         if (!token) return;
         const homeserver = `${url.protocol}//${url.host}`;
         done = true;
@@ -105,7 +115,32 @@ export async function extractMatrixCredentials(
       ),
     );
 
-    const captured = await Promise.race([credsPromise, timeout]);
+    let captured: MatrixCredentials;
+    try {
+      captured = await Promise.race([credsPromise, timeout]);
+    } catch (err) {
+      // On timeout, surface enough info to tell the three failure modes apart:
+      //   (a) chat.reddit.com never loaded         → page.url() still about:blank, almost no hosts
+      //   (b) page loaded, no Matrix host hit      → reddit hosts present, no matrix.*
+      //   (c) Matrix hit, but no Authorization     → matrix.* present with sawAuth: false
+      try {
+        const finalUrl = page.url();
+        const hostSummary = Array.from(seenHosts.entries())
+          .map(([host, info]) => `${host}=${info.count}${info.sawAuth ? '*' : ''}`)
+          .join(', ');
+        logger.error(
+          `[matrix] timeout diagnostics: finalUrl=${finalUrl} hosts=[${hostSummary || 'none'}]`,
+        );
+        const shotDir = path.dirname(cachePath);
+        if (!fs.existsSync(shotDir)) fs.mkdirSync(shotDir, { recursive: true });
+        const shotPath = path.join(shotDir, 'matrix-debug.png');
+        await page.screenshot({ path: shotPath, fullPage: true }).catch(() => undefined);
+        logger.error(`[matrix] saved debug screenshot to ${shotPath}`);
+      } catch (diagErr) {
+        logger.warn('[matrix] failed to collect timeout diagnostics:', diagErr);
+      }
+      throw err;
+    }
 
     // Resolve the user_id by calling /whoami so the caller knows who we are.
     const whoamiRes = await fetchWithTimeout(