Explain Flutter widget lifecycle methods.

Flutter StatefulWidget lifecycle methods:\n\n**createState()** - Creates mutable state\n**initState()** - Called once when widget inserted\n**didChangeDependencies()** - Called when dependencies change\n**build()** - Builds widget UI (called multiple times)\n**didUpdateWidget()** - Called when widget configuration changes\n**setState()** - Triggers rebuild\n**deactivate()** - Called when widget removed from tree\n**dispose()** - Called when widget permanently removed\n\n**Order:**\ncreateState() → initState() → didChangeDependencies() → build() → dispose()