feat: opt-in polecat self-terminate after gt done (polecat_self_terminate config)

[dannomayernotabot]

Summary

Opt-in config option. Adds polecat_self_terminate (default: false) under operational.daemon in settings/config.json. When enabled, polecats kill their tmux session 3 seconds after gt done instead of transitioning to IDLE. Default behavior is unchanged.

{"operational": {"daemon": {"polecat_self_terminate": true}}}

Understanding the Current Design

The persistent polecat model (gt-hdf8) is well-designed:

• "Done means idle, not dead" — sessions preserved for reuse
• Worktree reuse saves ~5s of git worktree add
• Identity persistence via CV chain across assignments
• Clean three-layer architecture (Identity/Sandbox/Session)

Why Opt-In Self-Termination Helps at Scale

At 10-30 concurrent polecats, the persistent model creates compounding issues:

1. Stale agent bead state — reused polecats retain old hook_bead, causing reaper to kill working polecats (fix: daemon idle reaper checks work bead assignee before killing polecats #3294)
2. Idle polecats never pick up new work — sit at prompt indefinitely after gt done
3. Token waste — reused sessions carry previous task context
4. Convoy dispatch confusion — idle polecats with stale state look like unassigned targets

What's Preserved

• Worktree reuse — FindIdlePolecat finds dead-session polecats, ReuseIdlePolecat creates fresh branch on existing worktree
• Identity persistence — agent beads and work history survive session death
• Default behavior unchanged — existing deployments are unaffected

Evidence

I have a long markdown file tracking all my findings throughout this process and documentation of what occurred, how i fixed, etc etc. happy to share if helpful/wanted

[codecov-commenter]

❌ 2 Tests Failed:

Tests completed	Failed	Passed	Skipped
9320	2	9318	48

View the top 2 failed test(s) by shortest run time

github.com/steveyegge/gastown/internal/cmd::TestStampLoop_InvalidValence

Stack Traces | 0s run time

=== RUN   TestStampLoop_InvalidValence
=== PAUSE TestStampLoop_InvalidValence
=== CONT  TestStampLoop_InvalidValence
    testing.go:1712: race detected during execution of test
--- FAIL: TestStampLoop_InvalidValence (0.00s)
=== RUN   TestStampLoop_InvalidValence/quality_too_high
--- PASS: TestStampLoop_InvalidValence/quality_too_high (0.00s)
=== RUN   TestStampLoop_InvalidValence/quality_negative
--- PASS: TestStampLoop_InvalidValence/quality_negative (0.00s)

github.com/steveyegge/gastown/internal/cmd::TestStampLoop_SelfStampFails

Stack Traces | 0s run time

=== RUN   TestStampLoop_SelfStampFails
=== PAUSE TestStampLoop_SelfStampFails
=== CONT  TestStampLoop_SelfStampFails
    testing.go:1712: race detected during execution of test
--- FAIL: TestStampLoop_SelfStampFails (0.00s)

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[steveyegge]

Superseded by #3302 (same feature — opt-in polecat self-terminate) which was merged.