ci: exempt canonical plugin registry source (#3736)

.github/scripts/pr-docs.cjs

@@ -232,6 +232,9 @@ function pathExemption(pathname) {
   if (pathname === 'docs' || pathname.startsWith('docs/')) {
     return 'documentation tree';
   }
+  if (pathname === 'plugin-registry/plugins.yaml') {
+    return 'canonical plugin registry source';
+  }
   if (/\.(?:md|mdx|markdown)$/i.test(pathname)) {
     return 'Markdown file';
   }

.github/scripts/pr-docs.test.cjs

@@ -39,6 +39,40 @@ test('recognized documentation-only paths are exempt', () => {
   assert.equal(result.exemptPaths.length, 9);
 });
 
+// @covers AC-CI-PR-DOCS-001.7
+test('the canonical plugin registry source is exempt', () => {
+  const result = validator.classifyChangedFiles([
+    { filename: 'plugin-registry/plugins.yaml', status: 'modified' },
+  ]);
+
+  assert.equal(result.requiresCoverage, false);
+  assert.deepEqual(result.triggeringPaths, []);
+  assert.deepEqual(result.exemptPaths, ['plugin-registry/plugins.yaml']);
+});
+
+// @covers AC-CI-PR-DOCS-001.7
+test('the registry exemption does not cover other registry files or mixed changes', () => {
+  const otherRegistryFile = validator.classifyChangedFiles([
+    { filename: 'plugin-registry/schema.json', status: 'modified' },
+  ]);
+  assert.equal(otherRegistryFile.requiresCoverage, true);
+  assert.deepEqual(otherRegistryFile.triggeringPaths, ['plugin-registry/schema.json']);
+
+  const registryBuilder = validator.classifyChangedFiles([
+    { filename: 'plugin-registry/build-index.mjs', status: 'modified' },
+  ]);
+  assert.equal(registryBuilder.requiresCoverage, true);
+  assert.deepEqual(registryBuilder.triggeringPaths, ['plugin-registry/build-index.mjs']);
+
+  const mixedChange = validator.classifyChangedFiles([
+    { filename: 'plugin-registry/plugins.yaml', status: 'modified' },
+    { filename: 'apps/backend/runtime.go', status: 'modified' },
+  ]);
+  assert.equal(mixedChange.requiresCoverage, true);
+  assert.deepEqual(mixedChange.exemptPaths, ['plugin-registry/plugins.yaml']);
+  assert.deepEqual(mixedChange.triggeringPaths, ['apps/backend/runtime.go']);
+});
+
 // @covers AC-CI-PR-DOCS-001.2
 test('recognized harness configuration paths are exempt', () => {
   const result = validator.classifyChangedFiles([