fix(#1001): make bug-969 hardening tests hermetic + move build tsbuildinfo out of shipped tree (regression from #996) (#1002)

* fix(#969): make bug-969 hardening tests hermetic and move build tsbuildinfo out of shipped tree (regression from #996)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(#969): self-heal legacy bin-local tsbuildinfo and make sentinel test hermetic (adversarial-review follow-ups)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* chore(changeset): set pr number to 1002

* docs(#1001): record DEFECT.SHARED-ARTIFACT-MUTATION-IN-CONCURRENT-TEST anti-pattern in CONTEXT.md

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

tsconfig.build.json

@@ -16,7 +16,7 @@
     "noEmitOnError": true,
     "skipLibCheck": true,
     "incremental": true,
-    "tsBuildInfoFile": "gsd-core/bin/tsconfig.build.tsbuildinfo"
+    "tsBuildInfoFile": "tsconfig.build.tsbuildinfo"
   },
   "include": ["src/**/*.cts"]
 }