Fix daemon monitor rule RPC timeouts

[WaldenLee2005]

Summary
Fixes daemon RPC timeouts and tokio runtime-drop panics around monitor rule and task-page workflows.

Changes

• Moves disk-heavy/session/task/monitor daemon RPC handlers onto detached blocking work so they do not stall the async WebSocket request loop.
• Updates monitor_rule_add and monitor_rule_delete to persist store changes synchronously, return a lightweight workflow snapshot, and refresh connection consumers on a named background thread.
• Updates monitor_memory_save to return the same lightweight workflow snapshot instead of doing the heavier full workflow list path.
• Adds regression coverage for monitor rule add/delete ensuring connection consumers still refresh after the RPC returns.