G-090 Notes: 9.0.x still carries the busy-thread finalize crash (e55a589d2b fix trunk-only)

Assisted-by: harness=opencode; primary-model=openrouter/moonshotai/kimi-k3; api-location=openrouter.ai

goals/G-090-shellfilter-shellthread-audit.md

@@ -63,3 +63,9 @@ none of this is currently pinned by committed tests):
   contract question.
 - Related: PUNK_TEST_UDPTEE watch mode contracts in src/tests/AGENTS.md; user registered the
   env var in punk::config's known-env-vars table 2026-07-18.
+- Upstream finalize state recorded 2026-07-29: the busy-thread finalize crash (tcl ticket
+  e55a589d2b - async send + busy thread + TCL_FINALIZE_ON_EXIT=1 segfault) was fixed on
+  trunk 2026-05-23 but explicitly NOT backported to 9.0, so 9.0.x runtimes (buildsuite
+  target 9.0.5) still carry it - relevant to any worker-lifecycle hazard probing under
+  this audit. Mechanism summary and derived work rules: root ARCHITECTURE.md "Process
+  exit and shutdown" and src/AGENTS.md Work Guidance exit-path bullet.