GDPR compliance: self-host all assets, add Impressum + Datenschutz

- Self-host Tailwind, Plotly, D3.js (no more CDN requests)
- Self-host Inter font (no more Google Fonts requests)
- Replace JetBrains Mono with system monospace font stack
- Zero external requests when visiting the site (GDPR-safe)
- Add /impressum page (§5 TMG, §18 MStV)
- Add /datenschutz page (DSGVO Art. 13/14)
- Hosting: Hetzner, no cookies, no tracking, no analytics
- Add Impressum/Datenschutz links to sidebar footer
- Configure Flask static_folder for local asset serving

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/webui/templates/base.html

@@ -4,10 +4,9 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>{% block title %}IETF Draft Analyzer{% endblock %}</title>
-    <script src="https://cdn.tailwindcss.com"></script>
-    <script src="https://cdn.plot.ly/plotly-2.35.0.min.js"></script>
-    <link rel="preconnect" href="https://fonts.googleapis.com">
-    <link href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet">
+    <script src="/static/js/tailwind.js"></script>
+    <script src="/static/js/plotly.min.js"></script>
+    <link rel="stylesheet" href="/static/css/fonts.css">
     <script>
         tailwind.config = {
             darkMode: 'class',
@@ -15,7 +14,7 @@
                 extend: {
                     fontFamily: {
                         sans: ['Inter', 'system-ui', 'sans-serif'],
-                        mono: ['JetBrains Mono', 'monospace'],
+                        mono: ['ui-monospace', 'SFMono-Regular', 'Menlo', 'Consolas', 'monospace'],
                     },
                 }
             }
@@ -135,8 +134,12 @@
                 </a>
             </div>
         </nav>
-        <div class="p-4 border-t border-slate-800 text-xs text-slate-600">
-            IETF Draft Analyzer v0.3
+        <div class="p-4 border-t border-slate-800 text-xs text-slate-600 space-y-1">
+            <div>IETF Draft Analyzer v0.3</div>
+            <div class="flex gap-3">
+                <a href="/impressum" class="hover:text-slate-400 transition">Impressum</a>
+                <a href="/datenschutz" class="hover:text-slate-400 transition">Datenschutz</a>
+            </div>
         </div>
     </aside>