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.

data/sharing.json

@@ -0,0 +1,57 @@
+{
+  "email": {
+    "icon": "email",
+    "title": "sharing.email",
+    "url": "mailto:?body=%s&subject=%s"
+  },
+  "facebook": {
+    "icon": "facebook",
+    "title": "sharing.facebook",
+    "url": "https://www.facebook.com/sharer/sharer.php?u=%s&quote=%s"
+  },
+  "line": {
+    "icon": "line",
+    "title": "sharing.line",
+    "url": "https://line.me/R/share?text=%s%%20%s"
+  },
+  "linkedin": {
+    "icon": "linkedin",
+    "title": "sharing.linkedin",
+    "url": "https://www.linkedin.com/shareArticle?mini=true&url=%s&title=%s"
+  },
+  "pinterest": {
+    "icon": "pinterest",
+    "title": "sharing.pinterest",
+    "url": "https://pinterest.com/pin/create/bookmarklet/?url=%s&description=%s"
+  },
+  "reddit": {
+    "icon": "reddit",
+    "title": "sharing.reddit",
+    "url": "https://reddit.com/submit/?url=%s&resubmit=true&title=%s"
+  },
+  "twitter": {
+    "icon": "x-twitter",
+    "title": "sharing.twitter",
+    "url": "https://twitter.com/intent/tweet/?url=%s&text=%s"
+  },
+  "whatsapp": {
+    "icon": "whatsapp",
+    "title": "sharing.whatsapp",
+    "url": "https://api.whatsapp.com/send?text=%s&resubmit=true&title=%s"
+  },
+  "telegram": {
+    "icon": "telegram",
+    "title": "sharing.telegram",
+    "url": "https://t.me/share/url?url=%s&resubmit=true&title=%s"
+  },
+  "bluesky": {
+    "icon": "bluesky",
+    "title": "sharing.bluesky",
+    "url": "https://bsky.app/intent/compose?text=%[2]s+%[1]s"
+  },
+  "mastodon": {
+    "icon": "mastodon",
+    "title": "sharing.mastodon",
+    "url": "https://share.joinmastodon.org/#text=%[2]s %[1]s"
+  }
+}