feat: implement Agent Chat Widget for entity pages

TASK_PHASE_AGENT_CHAT_WIDGET_MVP.md completed:

Backend:
- Add /api/v1/agents/{agent_id}/chat-room endpoint
- Add /api/v1/nodes/{node_id}/chat-room endpoint
- Add /api/v1/microdaos/{slug}/chat-room endpoint

Frontend:
- Create AgentChatWidget.tsx floating chat component
- Integrate into /agents/:agentId page
- Integrate into /nodes/:nodeId page
- Integrate into /microdao/:slug page

Ontology rule implemented:
'No page without agents' = ability to directly talk to agents on that page

apps/web/src/app/agents/[agentId]/page.tsx

@@ -21,6 +21,7 @@ import { updateAgentVisibility, AgentVisibilityUpdate } from '@/lib/api/agents';
 import { ensureOrchestratorRoom } from '@/lib/api/microdao';
 import { Bot, Settings, FileText, Building2, Cpu, MessageSquare, BarChart3, Users, Globe, Lock, Eye, EyeOff, ChevronLeft, Loader2, MessageCircle, PlusCircle } from 'lucide-react';
 import { CityChatWidget } from '@/components/city/CityChatWidget';
+import { AgentChatWidget } from '@/components/chat/AgentChatWidget';
 import { Button } from '@/components/ui/button';
 
 // Tab types
@@ -664,6 +665,9 @@ export default function AgentConsolePage() {
           </div>
         )}
       </div>
+      
+      {/* Floating Chat Widget */}
+      <AgentChatWidget contextType="agent" contextId={agentId} />
     </div>
   );
 }