## Changes
### agent_instance.py - Task Completion Counter Race Condition
- Changed `record_task_completion()` from read-modify-write pattern to
atomic SQL UPDATE
- Previously: Read instance → increment in Python memory → write back
- Now: Uses `UPDATE ... SET tasks_completed = tasks_completed + 1`
- Prevents lost updates when multiple concurrent task completions occur
### sprint.py - Row-Level Locking for Sprint Operations
- Added `with_for_update()` to `complete_sprint()` to prevent race
conditions during velocity calculation
- Added `with_for_update()` to `cancel_sprint()` for consistency
- Ensures atomic check-and-update for sprint status changes
## Impact
These fixes prevent:
- Counter metrics being lost under concurrent load
- Data corruption during sprint completion
- Race conditions with concurrent sprint status changes
Felipe Cardoso
e37a7690be