feat(ms-ai-architect): Sesjon 2 - registry-skjema (authority_source + course reservert)

build-registry leser na **Source:**/**Primary source:**-header via ny
lib/kb-headers.mjs (parseSourceHeader, 7 enhetstester) og logger dekning
(0/N i dag). Hver URL-entry far reserverte felt authority_source:null +
course:null (bakoverkompatibelt). Populering med korrekt semantikk utsatt
til verifiseringslaget (lag 3) - minimal-reservert per operator-valg.

Eksisterende status-felt (poll: tracked/not_in_sitemap/unpolled) urort for
a unnga kollisjon. kb-update 56 tester gronne.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01REiKFhP4w6xGXXqWKpPCJJ

tests/kb-update/test-kb-headers.test.mjs

@@ -0,0 +1,52 @@
+// tests/kb-update/test-kb-headers.test.mjs
+// Unit tests for scripts/kb-update/lib/kb-headers.mjs — parses the optional
+// **Source:** / **Primary source:** authority header from a KB reference file.
+// Coverage is 0% today (no file declares one yet); the parser is wired into
+// build-registry so authority_source can populate as files adopt the header.
+
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { parseSourceHeader } from '../../scripts/kb-update/lib/kb-headers.mjs';
+
+test('parseSourceHeader — **Source:** header', () => {
+  const content = '# Title\n\n**Source:** https://learn.microsoft.com/azure/foundry/concepts/x\n**Status:** GA\n';
+  assert.equal(
+    parseSourceHeader(content),
+    'https://learn.microsoft.com/azure/foundry/concepts/x'
+  );
+});
+
+test('parseSourceHeader — **Primary source:** alias', () => {
+  const content = '# Title\n\n**Primary source:** https://learn.microsoft.com/azure/ai-services/y\n';
+  assert.equal(
+    parseSourceHeader(content),
+    'https://learn.microsoft.com/azure/ai-services/y'
+  );
+});
+
+test('parseSourceHeader — case-insensitive label', () => {
+  const content = '**source:** https://learn.microsoft.com/azure/z\n';
+  assert.equal(parseSourceHeader(content), 'https://learn.microsoft.com/azure/z');
+});
+
+test('parseSourceHeader — no header returns null', () => {
+  const content = '# Title\n\n**Last updated:** 2026-04\n**Status:** GA\n**Category:** RAG\n';
+  assert.equal(parseSourceHeader(content), null);
+});
+
+test('parseSourceHeader — empty/garbage input returns null', () => {
+  assert.equal(parseSourceHeader(''), null);
+  assert.equal(parseSourceHeader(null), null);
+  assert.equal(parseSourceHeader(undefined), null);
+});
+
+test('parseSourceHeader — only scans the top of the file (header region)', () => {
+  // A Source-like line buried far below the header region must NOT be picked up.
+  const buried = '# Title\n' + 'x'.repeat(800) + '\n**Source:** https://learn.microsoft.com/late\n';
+  assert.equal(parseSourceHeader(buried), null);
+});
+
+test('parseSourceHeader — trims trailing whitespace from URL', () => {
+  const content = '**Source:**   https://learn.microsoft.com/azure/trim   \n';
+  assert.equal(parseSourceHeader(content), 'https://learn.microsoft.com/azure/trim');
+});