feat(mysql)!: promote to v1.0.0 — BeginTx with isolation levels, Stats, bump all deps to v1.0.0

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.

mysql.go

@@ -33,6 +33,7 @@ type Tx interface {
 type Client interface {
 	GetExecutor(ctx context.Context) Executor
 	Begin(ctx context.Context) (Tx, error)
+	BeginTx(ctx context.Context, opts *sql.TxOptions) (Tx, error)
 	Ping(ctx context.Context) error
 	HandleError(err error) error
 }
@@ -42,6 +43,7 @@ type Component interface {
 	launcher.Component
 	health.Checkable
 	Client
+	Stats() sql.DBStats
 }
 
 // UnitOfWork wraps operations in a single database transaction.
@@ -192,20 +194,34 @@ func (c *mysqlComponent) GetExecutor(ctx context.Context) Executor {
 	return db
 }
 
-func (c *mysqlComponent) Begin(ctx context.Context) (Tx, error) {
+func (c *mysqlComponent) BeginTx(ctx context.Context, opts *sql.TxOptions) (Tx, error) {
 	c.mu.RLock()
 	db := c.db
 	c.mu.RUnlock()
 	if db == nil {
 		return nil, fmt.Errorf("mysql: not initialized")
 	}
-	tx, err := db.BeginTx(ctx, nil)
+	tx, err := db.BeginTx(ctx, opts)
 	if err != nil {
 		return nil, err
 	}
 	return &mysqlTx{Tx: tx}, nil
 }
 
+func (c *mysqlComponent) Begin(ctx context.Context) (Tx, error) {
+	return c.BeginTx(ctx, nil)
+}
+
+func (c *mysqlComponent) Stats() sql.DBStats {
+	c.mu.RLock()
+	db := c.db
+	c.mu.RUnlock()
+	if db == nil {
+		return sql.DBStats{}
+	}
+	return db.Stats()
+}
+
 func (c *mysqlComponent) ExecContext(ctx context.Context, query string, args ...any) (sql.Result, error) {
 	c.mu.RLock()
 	db := c.db