feat: complete Event Log, Ledger, Memory, Cascade Router, Upgrade Queue, Activity Feed

This commit implements six major features:

1. Event Log System (src/swarm/event_log.py)
   - SQLite-based audit trail for all swarm events
   - Task lifecycle tracking (created, assigned, completed, failed)
   - Agent lifecycle tracking (joined, left, status changes)
   - Integrated with coordinator for automatic logging
   - Dashboard page at /swarm/events

2. Lightning Ledger (src/lightning/ledger.py)
   - Transaction tracking for Lightning Network payments
   - Balance calculations (incoming, outgoing, net, available)
   - Integrated with payment_handler for automatic logging
   - Dashboard page at /lightning/ledger

3. Semantic Memory / Vector Store (src/memory/vector_store.py)
   - Embedding-based similarity search for Echo agent
   - Fallback to keyword matching if sentence-transformers unavailable
   - Personal facts storage and retrieval
   - Dashboard page at /memory

4. Cascade Router Integration (src/timmy/cascade_adapter.py)
   - Automatic LLM failover between providers (Ollama → AirLLM → API)
   - Circuit breaker pattern for failing providers
   - Metrics tracking per provider (latency, error rates)
   - Dashboard status page at /router/status

5. Self-Upgrade Approval Queue (src/upgrades/)
   - State machine for self-modifications: proposed → approved/rejected → applied/failed
   - Human approval required before applying changes
   - Git integration for branch management
   - Dashboard queue at /self-modify/queue

6. Real-Time Activity Feed (src/events/broadcaster.py)
   - WebSocket-based live activity streaming
   - Bridges event_log to dashboard clients
   - Activity panel on /swarm/live

Tests:
- 101 unit tests passing
- 4 new E2E test files for Selenium testing
- Run with: SELENIUM_UI=1 pytest tests/functional/ -v --headed

Documentation:
- 6 ADRs (017-022) documenting architecture decisions
- Implementation summary in docs/IMPLEMENTATION_SUMMARY.md
- Architecture diagram in docs/architecture-v2.md

src/ws_manager/handler.py

@@ -119,6 +119,34 @@ class WebSocketManager:
     def connection_count(self) -> int:
         return len(self._connections)
 
+    async def broadcast_json(self, data: dict) -> int:
+        """Broadcast raw JSON data to all connected clients.
+        
+        Args:
+            data: Dictionary to send as JSON
+            
+        Returns:
+            Number of clients notified
+        """
+        import json
+        
+        message = json.dumps(data)
+        disconnected = []
+        count = 0
+        
+        for ws in self._connections:
+            try:
+                await ws.send_text(message)
+                count += 1
+            except Exception:
+                disconnected.append(ws)
+        
+        # Clean up dead connections
+        for ws in disconnected:
+            self.disconnect(ws)
+        
+        return count
+
     @property
     def event_history(self) -> list[WSEvent]:
         return list(self._event_history)