feat: photo landing page with favicon set

frontend/public/favicon.svg

@@ -0,0 +1,22 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 64 64">
+  <style>
+    .bg { fill: #1d4a79; }
+    .fg { fill: #ffffff; }
+    @media (prefers-color-scheme: dark) {
+      .bg { fill: #356fae; }
+    }
+  </style>
+  <rect class="bg" x="4" y="4" width="56" height="56" rx="14"/>
+  <!-- tower -->
+  <rect class="fg" x="26" y="22" width="12" height="28"/>
+  <!-- spire -->
+  <path class="fg" d="M32 8 L40 22 H24 Z"/>
+  <!-- cross -->
+  <rect class="fg" x="31.2" y="2.5" width="1.6" height="6"/>
+  <rect class="fg" x="29.4" y="4" width="5.2" height="1.6"/>
+  <!-- nave -->
+  <rect class="fg" x="14" y="36" width="12" height="14"/>
+  <path class="fg" d="M12 36 L20 28 L28 36 Z"/>
+  <!-- door knockout -->
+  <path class="bg" d="M29 50 v-5 a3 3 0 0 1 6 0 v5 Z"/>
+</svg>

frontend/public/photos/SOURCES.md

@@ -0,0 +1,19 @@
+# Landing-page photo sources
+
+All files in this directory are self-hosted (no hotlinking, no tracking).
+Licensed for free use including commercial purposes, no attribution
+required (Pexels License). Re-fetch any time:
+
+    docker compose exec api /opt/venv/bin/python \
+        /srv/kirche-einfach/frontend/scripts/fetch-photos.py
+
+Rejected during visual review (do NOT re-add without checking):
+US-megachurch conference screens, dark baroque interior, pandemic masks,
+Dutch-language documents.
+
+| File                   | Motif                          | Source |
+| ---------------------- | ------------------------------ | ------ |
+| hero-church.webp       | Stone church tower, blue sky   | https://www.pexels.com/photo/historic-church-with-bell-tower-in-germany-31630127/ |
+| church-pews.webp       | Bright empty pews, checkerboard| https://www.pexels.com/photo/church-pews-7566207/ |
+| paperwork-desk.webp    | Desk with stamps and forms     | https://www.pexels.com/photo/desk-with-documents-and-stamps-18687845/ |
+| team-laptop.webp       | Team collaborating at laptop   | https://www.pexels.com/photo/a-team-looking-at-a-laptop-7793702/ |

frontend/public/site.webmanifest

@@ -0,0 +1,22 @@
+{
+  "name": "Kirche Einfach",
+  "short_name": "Kirche",
+  "description": "KI-gestützte Verwaltungsplattform für Kirche",
+  "start_url": "/",
+  "display": "standalone",
+  "background_color": "#ffffff",
+  "theme_color": "#1d4a79",
+  "icons": [
+    {
+      "src": "/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "any maskable"
+    }
+  ]
+}