chore: clear dead test and allowlist leftovers of dropped runtimes

tests/repo-layout.test.cjs

@@ -7,7 +7,7 @@
  * (such as AGENTS.md) that would become an untracked source of truth running
  * in parallel with the canonical CONTEXT.md and docs/adr/ records.
  *
- * Context: historically bin/install.js (the since-retired local Copilot install
+ * Context: historically bin/install.js (the since-retired local install
  * path, issue #786) wrote an AGENTS.md to process.cwd() when run inside a repo
  * checkout. If such a file is ever committed, editors and AI tools that auto-load
  * repo-root instruction files will silently pick up an installer-generated
@@ -25,7 +25,7 @@ const ROOT = path.resolve(__dirname, '..');
 
 test('repo-layout: root AGENTS.md is not git-tracked — no ad-hoc AI instruction file committed alongside CONTEXT.md', () => {
   // An installer-generated AGENTS.md may exist on disk after a local install
-  // (historically the Copilot path, issue #786). What must NOT happen is
+  // (historically a retired install path, issue #786). What must NOT happen is
   // committing it to git, where editors and AI tools would silently pick up
   // the installer-generated stub instead of CONTEXT.md.
   const r = runGit(['ls-files', '--error-unmatch', 'AGENTS.md'], {