Add automatic cache-busting for static files

Use file modification time hash for base.js and tufte.css to
automatically bust browser cache when files are updated.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

kjvstudy_org/server.py

@@ -261,6 +261,23 @@ register_filters(templates.env)
 # Add global template variables
 templates.env.globals['disable_analytics'] = os.getenv("DISABLE_ANALYTICS", "false").lower() == "true"
 
+# Cache-busting for static files using file modification time
+import hashlib
+_static_hashes = {}
+
+def static_hash(filename):
+    """Generate a short hash based on file modification time for cache busting."""
+    if filename not in _static_hashes:
+        filepath = static_dir / filename
+        if filepath.exists():
+            mtime = int(filepath.stat().st_mtime)
+            _static_hashes[filename] = hashlib.md5(str(mtime).encode()).hexdigest()[:8]
+        else:
+            _static_hashes[filename] = "0"
+    return _static_hashes[filename]
+
+templates.env.globals['static_hash'] = static_hash
+
 # Initialize templates for route modules
 init_api_templates(templates)
 init_resources_templates(templates)

kjvstudy_org/templates/base.html

@@ -28,7 +28,7 @@
     <meta name="twitter:description" content="{% block twitter_description %}{% block description_plain %}Study the Authorized King James Version Bible{% endblock %}{% endblock %}"/>
     <meta name="twitter:image" content="{% block twitter_image %}https://kjvstudy.org/static/og-image.png{% endblock %}"/>
 
-    <link rel="stylesheet" href="/static/tufte.css"/>
+    <link rel="stylesheet" href="/static/tufte.css?v={{ static_hash('tufte.css') }}"/>
     <link rel="manifest" href="/static/manifest.json"/>
 
     <!-- Analytics opt-out detection (kr=1 parameter) -->
@@ -1577,7 +1577,7 @@
     </nav>
 
 
-    <script src="/static/base.js?v=20251203"></script>
+    <script src="/static/base.js?v={{ static_hash('base.js') }}"></script>
     <script type="text/javascript">
       {% if not disable_analytics %}
       // Gauges analytics (respects kr=1 opt-out)