Formalize control-plane route modes

[pmbstyle]

Summary

• formalize bounded control-plane routing for heartbeat, scheduler, and scheduled Octo control turns
• fix scheduled control completion token handling and tracing-context cleanup so successful control tasks stop collapsing into NO_USER_RESPONSE
• back off blocked scheduled octo_control tasks across ticks and restarts, surface suggested_execution_mode=worker, and show that guidance in scheduler status surfaces
• add a safe repair_scheduled_tasks flow that previews candidates by default and only applies unambiguous worker migrations with a valid worker template
• add curl, wget, and jq to the worker image for scheduled flows and existing worker templates that rely on them
• auto-connect worker MCP servers on demand