Add Gruvbox share theme + blog system for Trilium (anonymized)

Blog generator, publish manager, share scripts, theme CSS, highlight.js
bundles, font, favicon, templates and generated-reference outputs, plus an
English installation guide.

templates/blog_article.html

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+<p>Fill in the metadata below, then write your article body in this note.</p><h2>Metadata</h2>
+<ul>
+  <li><strong>Published</strong> – set this to true to publish the article on the blog index and in the RSS feed.</li>
+  <li><strong>URL Slug</strong> – optional short URL alias, e.g. <code>mpi400-keyboard-matrix</code>. Leave empty to use the note ID.</li>
+  <li><strong>Category</strong> – e.g. <code>Astrophotography</code>, <code>Electronic</code>, <code>Projects</code>.</li>
+  <li><strong>Date</strong> – article date in <code>YYYY-MM-DD</code> format.</li>
+  <li><strong>Summary</strong> – one or two sentences shown on the blog index and in the RSS feed.</li>
+  <li><strong>Tags</strong> – space-separated keywords, e.g. <code>mount onstep</code>.</li>
+</ul><h2>Placement</h2>
+<p>Put this note under a category folder inside <code>Blog Content</code> (e.g. <code>Projects</code>, <code>Astrophotography</code>, <code>Electronic</code>).</p><hr><h2>Article</h2>
+<p>Write your article here…</p>