Phase 4: CREATE Handler dynamic oplock granting
- Use OplockManager.can_grant() to determine oplock level
- Register OplockEntry if oplock granted
- Support ShareAccess compatibility checking
- Grant Level II if exclusive/batch oplock exists
Phase 6: CLOSE Handler oplock cleanup
- Unregister from OplockManager when file closed
- Only unregister if oplock_level > 0
All 229 tests pass.