Remove footer worker note; drop unused --subtle CSS variable

The footer line "Examples execute in Cloudflare Dynamic Python Workers."
is implementation trivia readers do not need on every page. --subtle was
declared at :root but never referenced anywhere in the codebase.

Author: claude

public/site.150df025a28b.css public/site.3611579bfe10.csspublic/site.150df025a28b.css renamed to public/site.3611579bfe10.css

@@ -1,3 +1,3 @@
 # Generated by scripts/fingerprint_assets.py. Do not edit by hand.
-ASSET_PATHS = {'SITE_CSS': '/site.150df025a28b.css', 'SYNTAX_JS': '/syntax-highlight.3b6c7f730d46.js', 'EDITOR_JS': '/editor.dd81f5171b14.js'}
-HTML_CACHE_VERSION = '4ab6c3b5d3eb'
+ASSET_PATHS = {'SITE_CSS': '/site.3611579bfe10.css', 'SYNTAX_JS': '/syntax-highlight.3b6c7f730d46.js', 'EDITOR_JS': '/editor.dd81f5171b14.js'}
+HTML_CACHE_VERSION = '1b40559f6f00'

public/site.css

@@ -23,6 +23,5 @@
     <nav><a class="brand" href="/">Python By Example</a><span class="nav-links"><a href="__REFERENCE_URL__">Python __PYTHON_VERSION__ docs</a><a href="/examples/hello-world">Start</a></span></nav>
   </header>
   <main>__CONTENT__</main>
-  <footer class="meta site-footer-note">Examples execute in Cloudflare Dynamic Python Workers.</footer>
 </body>
 </html>