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.

preview.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+
+# Usage: ./preview.sh [public|private]
+TARGET=$1
+
+if [ "$TARGET" != "public" ] && [ "$TARGET" != "private" ]; then
+    echo "Usage: $0 [public|private]"
+    exit 1
+fi
+
+# Cleanup function to run when the script exits
+cleanup() {
+    echo -e "\n🧹 Cleaning up symlinks and restoring default framework configurations..."
+    rm -rf content static config/_default/menus.en.toml
+    
+    # Restore the framework defaults from git checkout
+    git checkout -- content static config/_default/menus.en.toml &>/dev/null
+}
+
+# Trap exits (Ctrl+C, kill signals, normal exit) and run cleanup
+trap cleanup EXIT INT TERM
+
+echo "🚀 Setting up symlinks for: $TARGET docs..."
+
+# 1. Establish symlinks for content and static directories
+rm -rf content static
+ln -s /srv/docs/$TARGET content
+ln -s /srv/docs/$TARGET/static static
+
+# 2. Establish symlink for config override if it exists
+if [ -f "/srv/docs/$TARGET/config/_default/menus.en.toml" ]; then
+    rm -f config/_default/menus.en.toml
+    ln -s /srv/docs/$TARGET/config/_default/menus.en.toml config/_default/menus.en.toml
+fi
+
+# 3. Start the dev server (blocks until stopped)
+./run-dev.sh