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.

postgres.go

@@ -36,6 +36,7 @@ type Client interface {
 	// otherwise returns the pool.
 	GetExecutor(ctx context.Context) Executor
 	Begin(ctx context.Context) (Tx, error)
+	BeginTx(ctx context.Context, opts pgx.TxOptions) (Tx, error)
 	Ping(ctx context.Context) error
 	HandleError(err error) error
 }
@@ -45,6 +46,7 @@ type Component interface {
 	launcher.Component
 	health.Checkable
 	Client
+	Stats() *pgxpool.Stat
 }
 
 // UnitOfWork wraps operations in a single database transaction.
@@ -159,20 +161,34 @@ func (c *pgComponent) GetExecutor(ctx context.Context) Executor {
 	return pool
 }
 
-func (c *pgComponent) Begin(ctx context.Context) (Tx, error) {
+func (c *pgComponent) BeginTx(ctx context.Context, opts pgx.TxOptions) (Tx, error) {
 	c.mu.RLock()
 	pool := c.pool
 	c.mu.RUnlock()
 	if pool == nil {
 		return nil, fmt.Errorf("postgres: pool not initialized")
 	}
-	tx, err := pool.Begin(ctx)
+	tx, err := pool.BeginTx(ctx, opts)
 	if err != nil {
 		return nil, err
 	}
 	return &pgTx{Tx: tx}, nil
 }
 
+func (c *pgComponent) Begin(ctx context.Context) (Tx, error) {
+	return c.BeginTx(ctx, pgx.TxOptions{})
+}
+
+func (c *pgComponent) Stats() *pgxpool.Stat {
+	c.mu.RLock()
+	pool := c.pool
+	c.mu.RUnlock()
+	if pool == nil {
+		return &pgxpool.Stat{}
+	}
+	return pool.Stat()
+}
+
 func (c *pgComponent) Exec(ctx context.Context, sql string, args ...any) (pgconn.CommandTag, error) {
 	c.mu.RLock()
 	pool := c.pool