feat: Add presence heartbeat for Matrix online status

- matrix-gateway: POST /internal/matrix/presence/online endpoint
- usePresenceHeartbeat hook with activity tracking
- Auto away after 5 min inactivity
- Offline on page close/visibility change
- Integrated in MatrixChatRoom component

services/memory-orchestrator/backends/kb_filesystem.py

@@ -0,0 +1,75 @@
+import os
+import json
+from typing import Optional
+from models import MemoryItem
+from datetime import datetime
+
+class KnowledgeBaseBackend:
+    """
+    Long-term knowledge base (filesystem)
+    
+    Phase 3: Stub implementation
+    Stores docs, roadmaps, and structured knowledge
+    """
+    
+    def __init__(self, kb_path: str = "/data/kb"):
+        self.kb_path = kb_path
+    
+    async def initialize(self):
+        """Create KB directory"""
+        if not os.path.exists(self.kb_path):
+            try:
+                os.makedirs(self.kb_path, exist_ok=True)
+                print(f"✅ KB directory created: {self.kb_path}")
+            except Exception as e:
+                print(f"⚠️  Failed to create KB directory: {e}")
+                print("   Using in-memory stub")
+    
+    async def query(
+        self,
+        agent_id: str,
+        query_text: str,
+        limit: int = 5
+    ) -> list[MemoryItem]:
+        """
+        Query knowledge base
+        
+        Phase 3: Returns stub/empty results
+        Phase 4: Implement proper KB indexing and search
+        """
+        # Stub implementation for Phase 3
+        print(f"ℹ️  KB query (stub): {query_text[:50]}...")
+        
+        # Return empty results for now
+        # In Phase 4, this would:
+        # 1. Index docs/roadmaps with embeddings
+        # 2. Perform semantic search
+        # 3. Return relevant knowledge chunks
+        
+        return []
+    
+    async def store(
+        self,
+        agent_id: str,
+        microdao_id: str,
+        kind: str,
+        content: dict,
+        metadata: Optional[dict] = None
+    ) -> str:
+        """
+        Store knowledge base entry
+        
+        Phase 3: Stub implementation
+        """
+        # Stub for Phase 3
+        entry_id = f"kb-{datetime.now().timestamp()}"
+        print(f"ℹ️  KB store (stub): {entry_id}")
+        
+        # In Phase 4, would write to filesystem or DB
+        # with proper indexing
+        
+        return entry_id
+
+
+
+