docs: add database context manager to completed work

ROADMAP.md

@@ -348,6 +348,12 @@ PPF (Proxy Fetcher) is a Python 2 proxy scraping and validation framework design
 - [x] Thread-safe with lock for concurrent access
 - [x] Proper LRU eviction (move_to_end on hits, popitem oldest when full)
 
+### Database Context Manager (Done)
+- [x] Refactored all DB operations to use `_db_context()` context manager
+- [x] Connections guaranteed to close even on exceptions
+- [x] Removed deprecated `_prep_db()` and `_close_db()` methods
+- [x] `fetch_rows()` now accepts db parameter for cleaner dependency injection
+
 ---
 
 ## Technical Debt

TODO.md

@@ -656,6 +656,13 @@ becomes a constraint.
 - Process memory from /proc/self/status
 - GC statistics and collection counts
 
+### [x] Database Context Manager Refactoring
+- Refactored all DB operations to use `_db_context()` context manager
+- `prepare_jobs()`, `submit_collected()`, `_run()` now use `with self._db_context() as db:`
+- `fetch_rows()` accepts db parameter for dependency injection
+- Removed deprecated `_prep_db()` and `_close_db()` methods
+- Connections guaranteed to close even on exceptions
+
 ---
 
 ## Deployment Troubleshooting Log