Add debug_switchActiveStatus API for sequencer pause/resume control

[KyrinCode]

This PR adds a new debug API debug_switchActiveStatus that allows dynamic control of the sequencer's pause and resume states. When the sequencer is paused, it stops producing new blocks while keeping other RPC services online.
Features

• Dynamic Control: Pause/resume sequencer through RPC calls at any time
• Precise Pausing: Pauses after block processing completion, won't interrupt ongoing block processing
• Sequencer Validation: Only available on sequencer nodes, returns error on non-sequencer nodes
• RPC Continuity: Other RPC services remain functional during pause
  Implementation Details
• New File: zk/sequencer/sequencer_status.go - Global state manager with atomic operations
• API Interface: Added SwitchActiveStatus method in debug_api.go
• Integration: Added pause state check in stage_sequence_execute.go

[zjg555543]

Maybe we can use apollo