feat: DB-first architecture with lock-safe writes

- price_monitor: writes live prices to both JSON and mofin.db (holdings + live_prices + portfolio_summary)
- mofin_db: added execute_with_retry/commit_with_retry with exponential backoff on 'database is locked'
- mofin_db: increased timeout 5s->15s, added PRAGMA busy_timeout=15000
- price_monitor retry loop: fixed break-before-if-ok bug (was not retrying on write failure)
- DB connection: WAL mode + retry decorator for all write operations
- cash sync: preserves DB authoritative cash (JSON cash not pushed to DB)

This is the DB-first version. JSON writes remain for dashboard compatibility.
Next step: remove JSON writes entirely for full DB-only architecture.

scripts/verify_self_todo.py

@@ -0,0 +1,32 @@
+"""Verify self_todo_executor works with real DB"""
+import subprocess
+script = '/home/hmo/.hermes/profiles/position-analyst/scripts/self_todo_executor.py'
+
+# Test 1: DB_PATH
+content = open(script).read()
+if 'web-dashboard/data/mofin.db' in content:
+    print("DB_PATH: OK")
+else:
+    print("DB_PATH: WRONG")
+    exit(1)
+
+# Test 2: script can import and run
+try:
+    import importlib.util
+    spec = importlib.util.spec_from_file_location("executor", script)
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+    print("Import: OK")
+except Exception as e:
+    print(f"Import: FAIL -> {e}")
+    exit(1)
+
+# Test 3: get_pending works
+try:
+    rows = mod.get_pending()
+    print(f"get_pending: OK ({len(rows)} pending)")
+except Exception as e:
+    print(f"get_pending: FAIL -> {e}")
+    exit(1)
+
+print("\nAll checks passed.")