Site: search over the documentation (#60)

A search page whose index is the page itself: one item for each page and
each heading of the guide, the how-tos, the FAQ and the developer docs,
written by Zola from the pages' own content. A small script filters and
ranks them as you type. Nothing is fetched, so the Content-Security-Policy
needs nothing new; without JavaScript the page is a list of every heading.

The navigation gets a link, and the documentation's index pages a box that
is a plain form to /search/?q=. The devlog is not searched.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

site/templates/dev-index.html

@@ -11,6 +11,12 @@
 
   <div class="prose">{{ section.content | safe }}</div>
 
+  <form class="search-form search-mini" action="/search/" method="get" role="search">
+    <label class="sr" for="q">Search the documentation</label>
+    <input id="q" name="q" type="search" autocomplete="off" spellcheck="false" placeholder="Search the documentation">
+    <button class="btn n-md" type="submit">Search</button>
+  </form>
+
   <div class="cards">
     {% for path in section.subsections %}
     {% set sub = get_section(path=path) %}