feat(collector): add websocket

services/collector/db_writer.py

@@ -1,13 +1,13 @@
 #!/usr/bin/env python3
 """
 FR-2.3: Database Writer with Batch Processing
-Buffers audio metrics and writes in batches (50 records or 5 seconds)
+Buffers audio metrics and writes in batches
 """
 
 import asyncio
 import logging
 from datetime import datetime, timezone
-from typing import List, Optional
+from typing import List, Optional, final
 from dataclasses import dataclass
 
 import asyncpg
@@ -32,8 +32,8 @@ class DatabaseWriter:
     """
 
     BATCH_SIZE = 50
-    BATCH_TIMEOUT = 5.0  # seconds
-    SILENCE_THRESHOLD_DB = -30.0  # dB below = silence
+    BATCH_TIMEOUT: float = 5.0  # seconds
+    SILENCE_THRESHOLD_DB: float = -30.0  # dB below = silence
 
     def __init__(self, db_url: str):
         self.db_url = db_url
@@ -124,7 +124,6 @@ class DatabaseWriter:
             f"silence={is_silence} (buffer={len(self.buffer)})"
         )
 
-        # Flush if batch size reached
         if len(self.buffer) >= self.BATCH_SIZE:
             await self.flush()