migrate to decoupled Blowfish layout, fix TOC scrollspy, and update docs

- Theme Decoupling & Cleanup:
      - Fully decoupled and vendored the Blowfish theme directly into root directories (layouts/,
  assets/, static/, data/, i18n/).
      - De-registered and cleaned up legacy Git submodules (themes/blowfish, themes/hugo-admonitions)
  from the Git index to protect the build from upstream breakages.
      - Configured .gitignore to ignore development preview symlinks (content, static,
  config/_default/menus.en.toml), build folders (public/, resources/), and locks.

    - TOC & Layout Fixes:
      - Replaced the custom layouts/_default/single.html template with the Blowfish default to restore
  native container widths and the side-by-side flex layout.
      - Restored TOC to float on the right sidebar on desktop viewports and render inline on mobile
  viewports.
      - Fixed a parameter resolution bug in layouts/partials/toc.html by checking both .Site.Params.
  smartTOC and .Site.Params.article.smartTOC (where it is defined in params.toml).
      - Upgraded the TOC scrollspy JavaScript to target all '#TableOfContents' containers on the page,
  enabling highlight tracking on both desktop and mobile layouts.

    - Documentation Updates (README.md):
      - Restored YAML front matter metadata block at the top.
      - Added detailed notes on the CI/CD build process and Gitea runner deployment targets
  (/srv/www/docs-public and /srv/www/docs-private).
      - Added a categorized and sorted "Shortcodes Quick Reference" table at the top of the shortcodes
  section (ordered by Custom, Hugo Default, and Blowfish).
      - Documented custom shortcodes (Include, Screenshot, Raw HTML) and missing Hugo default
  shortcodes (Highlight, Instagram, Param, Ref, Relref, Twitter, Vimeo, Youtube).
      - Restructured headings to ensure all sub-shortcodes are H3, removed block break tags (<br/>),
  and appended horizontal separators (---) after H2 sections.

layouts/partials/series/series-closed.html

@@ -0,0 +1,5 @@
+{{ if .Params.series }}
+  <details class="mt-2 mb-5 overflow-hidden rounded-lg ms-0 ps-5">
+    {{ partial "series/series_base.html" . }}
+  </details>
+{{ end }}

layouts/partials/series/series.html

@@ -0,0 +1,7 @@
+{{ if .Params.series }}
+  <details
+    class="mt-2 mb-5 overflow-hidden rounded-lg ms-0 ps-5"
+    {{ if .Params.seriesOpened | default (.Site.Params.article.seriesOpened | default false) }}open{{ end }}>
+    {{ partial "series/series_base.html" . }}
+  </details>
+{{ end }}

layouts/partials/series/series_base.html

@@ -0,0 +1,25 @@
+{{ if .Params.series }}
+  <summary
+    class="py-1 text-lg font-semibold cursor-pointer bg-primary-200 text-neutral-800 -ms-5 ps-5 dark:bg-primary-800 dark:text-neutral-100">
+    {{ index .Params.series 0 }} -
+    {{ i18n "article.part_of_series" }}
+  </summary>
+  {{ $seriesName := strings.ToLower (index .Params.series 0) }}
+  {{ range $post := sort (index .Site.Taxonomies.series $seriesName) "Params.series_order" }}
+    {{ if eq $post.Permalink $.Page.Permalink }}
+      <div
+        class="py-1 border-dotted border-neutral-300 border-s-1 -ms-5 ps-5 dark:border-neutral-600">
+        {{ i18n "article.part" }} {{ $post.Params.series_order }}:
+        {{ i18n "article.this_article" }}
+      </div>
+    {{ else }}
+      <div
+        class="py-1 border-dotted border-neutral-300 border-s-1 -ms-5 ps-5 dark:border-neutral-600">
+        <a href="{{ $post.RelPermalink }}">
+          {{ i18n "article.part" }} {{ $post.Params.series_order }}:
+          {{ $post.Params.title }}
+        </a>
+      </div>
+    {{ end }}
+  {{ end }}
+{{ end }}