Session stuck in draining state after handoff, requires manual gc session wake

[azanar]

Problem

After gc handoff, the session enters draining state and never recovers. The controller does not wake it, requiring manual gc session wake.

Reproduction

1. Session running normally
2. gc handoff triggers (e.g., via PreCompact hook)
3. Session enters draining state
4. Controller never wakes it — stuck permanently

Related

• feat: handoff drain policy for session lifecycle #679 is a feature request for handoff drain policy, but this is a bug in the current behavior

Originally filed as azanar#1