feat(site-builder): pre-publish checklist and canonical link

Publish now runs client-side checks (image alt, meta description, title
length, H1, empty links, contrast, noindex landing, empty page) over the
current state and shows a grouped checklist with Fix links and
"Publish anyway". Adds ExportOptions.canonicalUrl -> <link rel="canonical">
after the favicon line in both Preview and export.

Refs #54

craft/src/editor/LoadGate.conflict.test.tsx

@@ -204,7 +204,7 @@ describe('conflict modal', () => {
     loadedThen('r1', [conflict409]);
     mount();
     await flush();
-    await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); });
+    await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await confirmChecklist();
     await flush();
     expect(q('[data-testid="conflict-modal"]')).not.toBeNull();
     expect(fetchMock.mock.calls.filter(([u]) => String(u).includes('action=publish'))).toHaveLength(0);
@@ -264,3 +264,10 @@ describe('revision and overwrite edge cases', () => {
     expect(saveBody(2).base_rev).toBe('r1');
   });
 });
+
+/** #54: the pre-publish checklist opens for these fixtures (an empty Home with no
+ *  meta description); these tests are about the publish path, so confirm it. */
+async function confirmChecklist() {
+  const b = q('[data-testid="publish-checklist-confirm"]') as HTMLElement | null;
+  if (b) await act(async () => { b.click(); });
+}

craft/src/editor/SaveSerialise.test.tsx

@@ -138,7 +138,7 @@ afterEach(() => {
 });
 
 const edit = () => act(() => { guard.markDirty(); });
-const clickPublish = async () => { await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await flush(); };
+const clickPublish = async () => { await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await confirmChecklist(); await flush(); };
 
 describe('saves are serialised', () => {
   test('a save requested during an in-flight publish waits, then saves with the rev the first save returned', async () => {
@@ -235,3 +235,10 @@ describe('autosave timer', () => {
     expect(calls('save').length).toBeGreaterThanOrEqual(2);
   });
 });
+
+/** #54: the pre-publish checklist opens for these fixtures (an empty Home with no
+ *  meta description); these tests are about the publish path, so confirm it. */
+async function confirmChecklist() {
+  const b = q('[data-testid="publish-checklist-confirm"]') as HTMLElement | null;
+  if (b) await act(async () => { b.click(); });
+}

craft/src/editor/SaveState.test.tsx

@@ -69,7 +69,7 @@ const flush = () => act(async () => { for (let i = 0; i < 10; i++) await Promise
 const calls = (action: string) => fetchMock.mock.calls.filter(([u]) => String(u).includes(`action=${action}`));
 const edit = () => act(() => { guard.markDirty(); });
 const clickSave = async () => { await act(async () => { q('button[aria-label="Save Draft"]')!.click(); }); await flush(); };
-const clickPublish = async () => { await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await flush(); };
+const clickPublish = async () => { await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await confirmChecklist(); await flush(); };
 
 function respondWith(handlers: { save?: unknown[]; publish?: unknown[] }) {
   const save = [...(handlers.save ?? [])];
@@ -368,7 +368,7 @@ describe('publish racing an edit', () => {
     });
     await mount();
     edit();
-    await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); });
+    await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await confirmChecklist();
     await flush();
     expect(calls('publish')).toHaveLength(1);
 
@@ -392,7 +392,7 @@ describe('publish racing an edit', () => {
     });
     await mount();
     edit();
-    await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); });
+    await act(async () => { q('button[aria-label="Publish to live site"]')!.click(); }); await confirmChecklist();
     await flush();
     const savesBefore = calls('save').length; // the publish's own save
     await act(async () => { vi.advanceTimersByTime(30_000); });
@@ -433,3 +433,10 @@ describe('populated project load', () => {
     expect(pill()).toBe('unsaved');
   });
 });
+
+/** #54: the pre-publish checklist opens for these fixtures (an empty Home with no
+ *  meta description); these tests are about the publish path, so confirm it. */
+async function confirmChecklist() {
+  const b = q('[data-testid="publish-checklist-confirm"]') as HTMLElement | null;
+  if (b) await act(async () => { b.click(); });
+}