release: v0.13.0 (#535)

Twenty-nine commits since v0.12.0. See CHANGELOG.md for the full list
and the upgrade notes.

Ten additions — the SEO package (site URL, robots.txt, sitemap.xml,
JSON-LD), slideshow mode, opt-in original downloads, copy-link,
previous/next album navigation, alt text from the Immich description,
per-album location precision, the update notice, a Help tab, and a
subpage cover grid separate from its photo grid. Two fixes: CJK album
slugs, and the lightbox control bar.

Photo of the Day (#476) was built on `dev` and reverted as not planned;
it never appears in a release.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

https://claude.ai/code/session_01DmsHVRL9yQvckUB1ZpVWre

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: ralksta <ralksta@users.noreply.github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

lib/__tests__/photoHash.test.ts

@@ -0,0 +1,58 @@
+import { describe, it, expect } from 'vitest';
+import { parsePhotoHash, buildPhotoHash, buildPhotoPermalink } from '@/lib/photoHash';
+
+describe('buildPhotoHash', () => {
+  it('presents the index 1-indexed', () => {
+    expect(buildPhotoHash(0)).toBe('#photo-1');
+    expect(buildPhotoHash(41)).toBe('#photo-42');
+  });
+});
+
+describe('parsePhotoHash', () => {
+  it('round-trips with buildPhotoHash', () => {
+    for (const index of [0, 1, 7, 250]) {
+      expect(parsePhotoHash(buildPhotoHash(index))).toBe(index);
+    }
+  });
+
+  it.each([
+    ['no hash', ''],
+    ['bare hash', '#'],
+    ['another anchor', '#gallery'],
+    ['missing number', '#photo-'],
+    ['not a number', '#photo-abc'],
+    ['negative', '#photo--3'],
+    ['trailing junk', '#photo-3x'],
+    ['leading junk', '#x-photo-3'],
+  ])('rejects %s', (_label, hash) => {
+    expect(parsePhotoHash(hash)).toBeNull();
+  });
+
+  it('rejects #photo-0, which has no 0-based index', () => {
+    expect(parsePhotoHash('#photo-0')).toBeNull();
+  });
+});
+
+describe('buildPhotoPermalink', () => {
+  const location = {
+    origin: 'https://folio.example',
+    pathname: '/travel/iceland',
+    search: '',
+  };
+
+  it('builds an absolute link to the photo', () => {
+    expect(buildPhotoPermalink(location, 2)).toBe('https://folio.example/travel/iceland#photo-3');
+  });
+
+  it('preserves an existing query string', () => {
+    expect(buildPhotoPermalink({ ...location, search: '?preview=true' }, 0)).toBe(
+      'https://folio.example/travel/iceland?preview=true#photo-1',
+    );
+  });
+
+  it('works at the site root', () => {
+    expect(buildPhotoPermalink({ ...location, pathname: '/' }, 0)).toBe(
+      'https://folio.example/#photo-1',
+    );
+  });
+});