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/fix_self_todo_path.py

@@ -0,0 +1,6 @@
+"""Fix DB_PATH in self_todo_executor.py"""
+path = '/home/hmo/.hermes/profiles/position-analyst/scripts/self_todo_executor.py'
+content = open(path).read()
+content = content.replace('projects/MoFin/data', 'web-dashboard/data')
+open(path, 'w').write(content)
+print("DB_PATH fixed to web-dashboard/data/mofin.db")