Add watchdog agent profile to command center

- Add 'watchdog' to KNOWN_PROFILES (5th agent)
- Custom status check via watchdog state file + kanban gateway fallback
- New /api/watchdog/status endpoint with scripts, plugins, heartbeat info
- Watchdog endpoint bypasses auth (public, non-sensitive)
- Update frontend PROFILE_ICONS + cache buster

static/app.js

@@ -279,7 +279,7 @@ let chatState = {
     sending: false,
 };
 
-const PROFILE_ICONS = { coder: '💻', assistant: '🤖', artist: '🎨', kanban: '📋' };
+const PROFILE_ICONS = { coder: '💻', assistant: '🤖', artist: '🎨', kanban: '📋', watchdog: '🛡️' };
 
 async function loadAgentProfiles() {
     try {

static/index.html

@@ -286,7 +286,7 @@
 
         </main>
     </div>
-    <script src="/static/app.js?v=2"></script>
+    <script src="/static/app.js?v=3"></script>
     <script src="/static/vault.js?v=2"></script>
 </body>
 </html>