- replace batch attribute updates with token, field, and value requests
- support parameter value updates for writable attribute groups
- support measurement mode switching and manual value updates
- record bounded measurement operation logs in PostgreSQL
- add jsonb array serialization for measurement operations
- add transaction failure context and error-chain support
- add unit tests for validation and update workflows
- run 5 independent DB queries concurrently via errgroup.WithContext
- add ctx parameter and bind db with WithContext for cancellation support
- replace silent error swallowing (if err == nil) with wrapped error returns
- promote golang.org/x/sync to direct dependency in go.mod