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>

Dockerfile

@@ -0,0 +1,27 @@
+FROM node:20-bookworm-slim
+
+WORKDIR /app
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    python3 make g++ \
+  && rm -rf /var/lib/apt/lists/*
+
+COPY package.json ./
+RUN npm install --omit=dev
+
+COPY src ./src
+COPY public ./public
+
+# Prepare mount points with UID 1000 ownership so named volumes inherit it.
+RUN mkdir -p /data/db /data/uploads /webdav-config \
+  && chown -R 1000:1000 /data /webdav-config /app
+
+ENV NODE_ENV=production \
+    PORT=3000 \
+    UPLOAD_ROOT=/data/uploads \
+    DB_PATH=/data/db/app.db \
+    WEBDAV_CONFIG_DIR=/webdav-config
+
+EXPOSE 3000
+
+CMD ["node", "src/server.js"]