Add PunktFri Flask landing page

- Landing page with hero, problemet, målgruppe, idé, disclaimer sections
- Signup form → SQLite + file log (navn, email, domæner, egne_ns, kommentar)
- /tak confirmation page
- /admin with HTTP Basic Auth
- /health endpoint
- Mobile-first minimal CSS, Danish throughout
- Honest 'under undersøgelse' framing — no premature organisational claims

templates/admin.html

@@ -0,0 +1,47 @@
+{% extends "base.html" %}
+
+{% block title %}Admin — PunktFri{% endblock %}
+
+{% block content %}
+<div class="admin-section">
+    <h1>Tilmeldinger</h1>
+    <p class="admin-meta">{{ count }} tilmelding{{ 'er' if count != 1 else '' }} i alt</p>
+
+    {% if signups %}
+    <div class="table-wrapper">
+        <table class="signups-table">
+            <thead>
+                <tr>
+                    <th>#</th>
+                    <th>Navn</th>
+                    <th>E-mail</th>
+                    <th>Domæner</th>
+                    <th>Egne NS</th>
+                    <th>Kommentar</th>
+                    <th>Tidspunkt</th>
+                </tr>
+            </thead>
+            <tbody>
+                {% for s in signups %}
+                <tr>
+                    <td>{{ s.id }}</td>
+                    <td>{{ s.navn }}</td>
+                    <td>{{ s.email }}</td>
+                    <td>{{ s.domaener }}</td>
+                    <td>
+                        <span class="badge-{{ s.egne_ns }}">{{ s.egne_ns | upper }}</span>
+                    </td>
+                    <td>{{ s.kommentar or '—' }}</td>
+                    <td style="white-space:nowrap; color:#6b7280;">{{ s.timestamp }}</td>
+                </tr>
+                {% endfor %}
+            </tbody>
+        </table>
+    </div>
+    {% else %}
+    <div class="empty-state">
+        <p>Ingen tilmeldinger endnu.</p>
+    </div>
+    {% endif %}
+</div>
+{% endblock %}