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/schema.html

@@ -0,0 +1,73 @@
+{{ if .IsHome -}}
+  <script type="application/ld+json">
+  {
+    "@context": "https://schema.org",
+    "@type": "WebSite",
+    "@id": {{ site.Home.Permalink | safeURL }},
+    "name": "{{ .Site.Title | safeJS }}",
+    {{ with .Site.Params.description }}"description": "{{ . | safeJS }}",{{ end }}
+    {{ with .Site.Language.Locale }}"inLanguage": "{{ . }}",{{ end }}
+    "url": {{ site.Home.Permalink | safeURL }},
+    {{ with .Site.Params.keywords }}"keywords": {{ . }},{{ end }}
+    "publisher" : {
+      "@type": "Person",
+      "name": "{{ .Site.Params.Author.name | safeJS }}"
+    }
+  }
+  </script>
+{{ else }}
+  {{- $iso8601 := "2006-01-02T15:04:05-07:00" -}}
+  <script type="application/ld+json">
+  [{
+    "@context": "https://schema.org",
+    "@type": "Article",
+    "articleSection": "{{ (site.GetPage .Section).Title | safeJS }}",
+    "name": "{{ .Title | safeJS }}",
+    "headline": "{{ .Title | safeJS }}",
+    {{ with .Description }}"description": "{{ . | safeJS }}",{{ end }}
+    {{ with .Site.Language.Locale }}"inLanguage": "{{ . }}",{{ end }}
+    "url" : {{ .Permalink }},
+    "author" : {
+      "@type": "Person",
+      "name": "{{ .Site.Params.Author.name | safeJS }}"
+    },
+    {{ with .PublishDate }}"copyrightYear": "{{ .Format "2006" }}",{{ end }}
+    {{ with .Date }}"dateCreated": "{{ .Format $iso8601 }}",{{ end }}
+    {{ with .PublishDate }}"datePublished": "{{ .Format $iso8601 }}",{{ end }}
+    {{ with .ExpiryDate }}"expires": "{{ .Format $iso8601 }}",{{ end }}
+    {{ with .Lastmod }}"dateModified": "{{ .Format $iso8601 }}",{{ end }}
+    {{ if .Keywords }}
+    {{ with .Keywords }}"keywords": {{ . }},{{ end }}
+    {{ else }}
+    {{ with .Params.tags }}"keywords": {{ . }},{{ end }}
+    {{ end }}
+    "mainEntityOfPage": "true",
+    "wordCount": "{{ .WordCount }}"
+  }{{ if site.Params.enableStructuredBreadcrumbs | default false }},
+  {
+    "@context": "https://schema.org",
+    "@type": "BreadcrumbList",
+    "itemListElement": [
+      {{- $position := 0 -}}
+      {{- range .Ancestors -}}
+        {{- if not .IsHome -}}
+          {{- $position = add $position 1 -}}
+          {
+            "@type": "ListItem",
+            "position": {{ $position }},
+            "name": "{{ .Title }}",
+            "item": {{ .Permalink }}
+          },
+        {{- end -}}
+      {{- end -}}
+      {{- $position = add $position 1 -}}
+      {
+        "@type": "ListItem",
+        "position": {{ $position }},
+        "name": "{{ .Title }}",
+        "item": {{ .Permalink }}
+      }
+    ]
+  }{{ end }}]
+  </script>
+{{ end }}