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

---------

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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>

content/settings.yaml.example

@@ -19,6 +19,9 @@ lang: "en"
 #   titleTemplate: "%s | My Portfolio" # Template for subpages (%s is replaced with subpage/album title)
 #   noIndex: false # Set to true to hide from search engines
 #   noFollow: false # Set to true to prevent search engines from following links
+#   # Licence your photographs are published under, emitted as structured
+#   # data on album pages. A URL or a short identifier.
+#   license: "https://creativecommons.org/licenses/by-nc-nd/4.0/"
 
 # ── Site password (optional) ─────────────────────────────────────
 # Puts the WHOLE public site behind one password — useful while a portfolio
@@ -77,6 +80,14 @@ theme:
   # heroStyle: "split" # split, fullbleed, minimal, stacked, typographic, mosaic, cover (EXPERIMENTAL)
   #   Note: "mosaic" needs at least 3 hero images in gallery.yaml (optimal: 6)
 
+# ── Site URL ─────────────────────────────────────────────────────
+# The address this portfolio is reachable at, e.g. https://folio.example
+# Needed for sitemap.xml, the feed and structured data: those are built
+# without a request, so the host cannot be derived from one. Left empty,
+# the sitemap stays empty rather than guessing a wrong address.
+# The SITE_URL environment variable is used when this is not set.
+# url: "https://folio.example"
+
 # ── Grid configuration ───────────────────────────────────────────
 grid:
   columns: 3