Guard Timberborn launch intent

[Ustice]

Summary

• Closes Harden live QA launch orchestration against duplicate Timberborn launch attempts #70 by adding a shared short-lived launch-intent guard around helper-driven open -b com.mechanistry.timberborn calls.
• Logs launch, attach, activation, duplicate refusal, and startup-timeout intent so QA can distinguish first launch from attach/focus paths.
• Wires the guard into both load-latest-save-and-unpause.ts and check-timberborn-startup.ts.

Verification

• bun test tests/timberborn-startup.test.ts
• bun run typecheck
• git diff --check

Review

• Reviewer initially found a P1 TTL mismatch where a shorter second helper could shorten a longer recorded launch window.
• Reworked to use the max of recorded marker TTL and current caller TTL.
• Reviewer recheck passed with no findings.

Notes

This prevents duplicate helper-driven launch intent. It cannot prevent a manual shell or human open -b outside these scripts.