feat(postgres)!: promote to v1.0.0 — BeginTx with pgx options, Stats, bump all deps to v1.0.0

Add BeginTx(ctx, pgx.TxOptions) to Client interface for explicit isolation level and
read-only transaction control; Begin refactored as a convenience wrapper calling
BeginTx(ctx, pgx.TxOptions{}). Add Stats() *pgxpool.Stat 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.

CHANGELOG.md

@@ -5,6 +5,25 @@ All notable changes to this module will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this module adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.0] — 2026-05-12
+
+### Added
+
+- `Client.BeginTx(ctx context.Context, opts pgx.TxOptions) (Tx, error)` — starts a transaction with explicit isolation level and read-only options using pgx-native `pgx.TxOptions`.
+- `Component.Stats() *pgxpool.Stat` — returns connection pool metrics (`TotalConns`, `IdleConns`, `AcquiredConns`, `MaxConns`, etc.) for observability and alerting; returns a zero-value `*pgxpool.Stat` when called before `OnInit`.
+
+### Changed
+
+- `Client.Begin(ctx context.Context) (Tx, error)` — refactored as a convenience wrapper calling `BeginTx(ctx, pgx.TxOptions{})`; behavior is identical, no breaking change.
+- All micro-lib dependencies bumped from v0.9.0 to v1.0.0: `logz`, `health`, `launcher`, `xerrors`.
+
+### Unchanged
+
+All other API (`Executor`, `Tx`, `Client`, `Component`, `UnitOfWork`, `Config`, `New`,
+`NewUnitOfWork`, `HandleError`) is API-compatible with v0.9.0.
+
+[1.0.0]: https://code.nochebuena.dev/go/postgres/releases/tag/v1.0.0
+
 ## [0.9.0] - 2026-03-18
 
 ### Added