Stop durable approval waits during daemon drain

[Aaronontheweb]

Change

• Stop the current tool task when every unfinished call waits for a durable approval.
• Wait for the task to stop before the session acknowledges drain.
• Keep journaled approvals, sibling results, and original turn authority for cold recovery.
• Keep the current bounded drain path for active siblings and accepted buffered input.
• Update SPEC-011, the session-resume OpenSpec contract, and the operations skill.

Evidence

• The new actor test timed out against the baseline, then passed after this change.
• The actor project passed: 4,022 passed, six skipped.
• The Spark2 Skill Discovery eval passed: 8/8 cases, one run each.
• Slopwatch found zero issues. Header verification and OpenSpec validation passed.

Scope

The actor still uses the current drain limit for active model calls and other tool states. The later input recovery PR addresses those states. No live daemon restart took place.

Stack

This PR targets the approved plan in #2201.

[Aaronontheweb]

Superseded by #2208. The new PR uses the same commit and belongs to native stack #2212.