Add file upload portal with per-customer links and WebDAV admin access

- Customer upload via token link (no login), optional password + expiry,
  drag & drop for files and folders with preserved structure
- Admin portal with setup wizard, role-based users (admin/staff),
  per-customer WebDAV access rules (read/write), session auth
- WebDAV container (Debian apache2) with htpasswd + access.conf
  auto-generated from the SQLite DB and reloaded via inotifywait
- Configurable public base URL and janitor cron interval in admin UI;
  janitor reconciles the uploads table with the filesystem

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -0,0 +1,32 @@
+services:
+  app:
+    build: .
+    container_name: simple-file-upload
+    restart: unless-stopped
+    user: "1000:1000"
+    ports:
+      - "${APP_PORT:-3500}:3000"   # Web (Upload + Admin)
+    environment:
+      DB_PATH: /data/db/app.db
+      UPLOAD_ROOT: /data/uploads
+      WEBDAV_CONFIG_DIR: /webdav-config
+      # PUBLIC_BASE_URL can be set via the admin Einstellungen tab instead.
+    volumes:
+      - ./data/db:/data/db              # SQLite DB liegt hier neben docker-compose.yml
+      - ./data/uploads:/data/uploads    # Kunden-Uploads
+      - webdav-config:/webdav-config    # dynamisch generierte htpasswd + access.conf
+
+  webdav:
+    build: ./webdav
+    container_name: simple-file-upload-webdav
+    restart: unless-stopped
+    ports:
+      - "${WEBDAV_PORT:-1900}:80"   # WebDAV — Login via DB-Benutzer
+    environment:
+      WEBDAV_CONFIG_DIR: /webdav-config
+    volumes:
+      - ./data/uploads:/data/uploads
+      - webdav-config:/webdav-config
+
+volumes:
+  webdav-config: