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/secondme-service/models.py

@@ -0,0 +1,68 @@
+"""
+Pydantic Models для Second Me Service
+"""
+
+from pydantic import BaseModel, Field
+from typing import Optional, List
+from datetime import datetime
+
+
+# =============================================================================
+# Second Me Session
+# =============================================================================
+
+class SecondMeSession(BaseModel):
+    id: str
+    user_id: str
+    agent_id: Optional[str] = None
+    created_at: datetime
+    last_interaction_at: Optional[datetime] = None
+
+
+# =============================================================================
+# Second Me Message
+# =============================================================================
+
+class SecondMeMessageBase(BaseModel):
+    content: str = Field(..., min_length=1, max_length=10000)
+
+
+class SecondMeMessageCreate(SecondMeMessageBase):
+    role: str = Field(..., pattern="^(user|assistant)$")
+
+
+class SecondMeMessageRead(SecondMeMessageBase):
+    id: str
+    session_id: str
+    user_id: str
+    role: str
+    tokens_used: Optional[int] = None
+    latency_ms: Optional[int] = None
+    created_at: datetime
+
+
+# =============================================================================
+# Second Me Invoke
+# =============================================================================
+
+class SecondMeInvokePayload(BaseModel):
+    prompt: str = Field(..., min_length=1, max_length=5000)
+
+
+class SecondMeInvokeResponse(BaseModel):
+    response: str
+    tokens_used: int
+    latency_ms: int
+    history: List[dict] = []
+
+
+# =============================================================================
+# Second Me Profile
+# =============================================================================
+
+class SecondMeProfile(BaseModel):
+    user_id: str
+    agent_id: str
+    total_interactions: int
+    last_interaction: Optional[datetime] = None
+