chore(db): wire ensure_venv() into connector scripts

Add venv auto-activation to audio_batch, audio_connector,
image_connector, qdrant_connector, and trellis_connector.
Scripts re-exec into .venv/bin/python when invoked outside
the venv, with a friendly error if .venv is missing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tooling/db/audio_batch.py

@@ -8,12 +8,18 @@ Usage:
     python3 audio_batch.py manifest.json [--dry-run] [--only ID,ID,...] [--skip-existing]
 """
 
-import json
-import math
-import os
-import struct
-import subprocess
 import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent))
+
+from common import ensure_venv  # noqa: E402
+
+ensure_venv()
+
+import json
+import os
+import subprocess
 import wave
 
 import numpy as np