fix(db): sqlite connector always reads/writes main worktree database

Same fix as the ticket CLI — uses git rev-parse --git-common-dir to
resolve DB path to the main worktree. Prevents WAL/journal pollution
when sqlite-query or sqlite-exec are called from feature branches.

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

db/connectors/sqlite_connector.py

@@ -13,6 +13,7 @@ Usage:
 import json
 import os
 import sqlite3
+import subprocess
 import sys
 from pathlib import Path
 
@@ -25,12 +26,26 @@ CONFIG_PATH = SCRIPT_DIR / "config.json"
 SCHEMA_PATH = SCRIPT_DIR.parent / "schema.sql"
 
 
+def _main_worktree():
+    """Find the main worktree root via git's common dir."""
+    try:
+        common = subprocess.check_output(
+            ["git", "rev-parse", "--git-common-dir"],
+            stderr=subprocess.DEVNULL, text=True
+        ).strip()
+        return Path(common).resolve().parent
+    except (subprocess.CalledProcessError, OSError):
+        return SCRIPT_DIR.parent.parent
+
+
 def load_config():
     """Load config.json and resolve the SQLite database path."""
     with open(CONFIG_PATH, "r") as f:
         cfg = json.load(f)
-    # Resolve sqlite_db relative to the connectors directory
-    db_path = (SCRIPT_DIR / cfg["sqlite_db"]).resolve()
+    # Always resolve DB path in the main worktree to avoid
+    # WAL/journal pollution on feature branches causing merge conflicts.
+    main_root = _main_worktree()
+    db_path = (main_root / "db" / "commonwealth.db").resolve()
     cfg["sqlite_db_resolved"] = str(db_path)
     return cfg