Add BeginTx(ctx, *sql.TxOptions) to Client interface for explicit transaction isolation
level control; Begin refactored as a convenience wrapper calling BeginTx(ctx, nil).
Add Stats() sql.DBStats to Component interface for connection pool observability.
Bump all micro-lib dependencies (logz, health, launcher, xerrors) from v0.9.0 to v1.0.0.
API committed as stable.
database/sql-backed MySQL client with launcher lifecycle, health check, unit-of-work via context injection, and structured error mapping.
What's included:
- Executor / Tx / Client / Component interfaces using database/sql native types (sql.Result, *sql.Rows, *sql.Row)
- Tx.Commit() / Tx.Rollback() without ctx, matching the honest database/sql contract
- New(logger, cfg) constructor; *sql.DB opened in OnInit
- Config struct with env-tag support for all pool tuning parameters
- UnitOfWork via context injection; GetExecutor(ctx) returns active *sql.Tx or *sql.DB
- HandleError mapping MySQLError.Number to xerrors codes (1062 → AlreadyExists, 1216/1217/1451/1452 → InvalidInput, ErrNoRows → NotFound)
- Driver imported as mysqldrv alias to avoid package name collision
- health.Checkable at LevelCritical; HealthCheck delegates to db.PingContext
Tested-via: todo-api POC integration
Reviewed-against: docs/adr/
