refactor(db): move ticketing database to shared worktree location

The SQLite database now lives at ../settledreach.db, shared across all
git worktrees. This eliminates binary merge conflicts that occurred
whenever two branches modified the database independently.

All Python connectors (ticket CLI, sqlite_connector, decisions_sync)
now resolve the DB path relative to their own location — three levels
up from db/connectors/ reaches the worktree parent. The _main_worktree()
git-rev-parse pattern and config.json sqlite_db key are removed.

The database file is untracked from git; a backup mechanism commits
snapshots through the main branch (see following commits).

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

db/connectors/sqlite_connector.py

@@ -13,7 +13,6 @@ Usage:
 import json
 import os
 import sqlite3
-import subprocess
 import sys
 from pathlib import Path
 
@@ -24,29 +23,15 @@ from pathlib import Path
 SCRIPT_DIR = Path(__file__).resolve().parent
 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
+# Shared database lives in the parent of all worktrees (three levels up from db/connectors/).
+DB_PATH = (SCRIPT_DIR / ".." / ".." / ".." / "settledreach.db").resolve()
 
 
 def load_config():
     """Load config.json and resolve the SQLite database path."""
     with open(CONFIG_PATH, "r") as f:
         cfg = json.load(f)
-    # 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)
+    cfg["sqlite_db_resolved"] = str(DB_PATH)
     return cfg