feat: update upload functionality and permissions for document handling

- Removed the `upsert` option from the file upload in `uploadDoc` function to prevent unintended overwrites.
- Enhanced German translations in `i18n.js` for better clarity and consistency in the admin interface.
- Added new CSS styles for link interactions to improve user experience in `styles.css`.
- Updated Supabase SQL migration to grant additional permissions for anonymous users to insert and update storage objects, ensuring proper functionality during the booking flow.

Co-authored-by: Copilot <copilot@github.com>

docker-compose.yml

@@ -214,6 +214,7 @@ services:
       - /mnt/user/appdata/mc-cars/supabase/migrations/04-kaution-weekend-km.sql:/sql/04-kaution-weekend-km.sql:ro
       - /mnt/user/appdata/mc-cars/supabase/migrations/05-create-lead-rpc.sql:/sql/05-create-lead-rpc.sql:ro
       - /mnt/user/appdata/mc-cars/supabase/migrations/06-admin-pricing-documents.sql:/sql/06-admin-pricing-documents.sql:ro
+      - /mnt/user/appdata/mc-cars/supabase/migrations/07-sales-orders.sql:/sql/07-sales-orders.sql:ro
     entrypoint: ["sh","-c"]
     command:
       - |
@@ -236,6 +237,7 @@ services:
         psql "postgresql://postgres:$$PGPASSWORD@db:5432/postgres" -v ON_ERROR_STOP=1 -f /sql/04-kaution-weekend-km.sql
         psql "postgresql://postgres:$$PGPASSWORD@db:5432/postgres" -v ON_ERROR_STOP=1 -f /sql/05-create-lead-rpc.sql
         psql "postgresql://postgres:$$PGPASSWORD@db:5432/postgres" -v ON_ERROR_STOP=1 -f /sql/06-admin-pricing-documents.sql
+        psql "postgresql://postgres:$$PGPASSWORD@db:5432/postgres" -v ON_ERROR_STOP=1 -f /sql/07-sales-orders.sql
         echo "post-init done."
     restart: "no"
     networks: [mccars]
@@ -339,3 +341,71 @@ services:
       - "55580:80"
     networks: [mccars]
     logging: { driver: json-file, options: { max-size: "10m", max-file: "3" } }
+
+  # -------------------------------------------------------------------------
+  # Admin panel (separate nginx instance on its own port)
+  # -------------------------------------------------------------------------
+  web-admin:
+    image: nginx:1.27-alpine
+    container_name: mccars-web-admin
+    restart: unless-stopped
+    depends_on:
+      - kong
+    environment:
+      SUPABASE_URL: ${SUPABASE_PUBLIC_URL}
+      SUPABASE_ANON_KEY: ${ANON_KEY}
+    volumes:
+      - /mnt/user/appdata/mc-cars/frontend:/usr/share/nginx/html
+      - /mnt/user/appdata/mc-cars/frontend/nginx-admin.conf:/etc/nginx/conf.d/default.conf:ro
+    entrypoint: ["/bin/sh", "-c", "printf 'window.MCCARS_CONFIG={SUPABASE_URL:\"%s\",SUPABASE_ANON_KEY:\"%s\"};\\n' \"$$SUPABASE_URL\" \"$$SUPABASE_ANON_KEY\" > /usr/share/nginx/html/config.js && exec nginx -g 'daemon off;'"]
+    ports:
+      - "55581:80"
+    networks: [mccars]
+    logging: { driver: json-file, options: { max-size: "10m", max-file: "3" } }
+
+  # -------------------------------------------------------------------------
+  # n8n - workflow automation (connects to Supabase via Postgres + REST)
+  # UI: http://localhost:55590
+  # -------------------------------------------------------------------------
+  n8n:
+    image: n8nio/n8n:latest
+    container_name: mccars-n8n
+    restart: unless-stopped
+    depends_on:
+      db:
+        condition: service_healthy
+      kong:
+        condition: service_started
+    environment:
+      # Core
+      N8N_HOST: 0.0.0.0
+      N8N_PORT: 5678
+      N8N_PROTOCOL: http
+      WEBHOOK_URL: http://localhost:55590/
+      N8N_ENCRYPTION_KEY: ${N8N_ENCRYPTION_KEY}
+
+      # Database (n8n stores its own data in the same Postgres)
+      DB_TYPE: postgresdb
+      DB_POSTGRESDB_HOST: db
+      DB_POSTGRESDB_PORT: 5432
+      DB_POSTGRESDB_DATABASE: ${POSTGRES_DB}
+      DB_POSTGRESDB_USER: postgres
+      DB_POSTGRESDB_PASSWORD: ${POSTGRES_PASSWORD}
+      DB_POSTGRESDB_SCHEMA: n8n
+
+      # Auto-create owner account on first boot
+      N8N_DEFAULT_USER_EMAIL: ${N8N_USER_EMAIL}
+      N8N_DEFAULT_USER_PASSWORD: ${N8N_USER_PASSWORD}
+
+      # Timezone
+      GENERIC_TIMEZONE: Europe/Vienna
+      TZ: Europe/Vienna
+
+      # Allow importing workflows from filesystem
+      N8N_USER_FOLDER: /home/node/.n8n
+    volumes:
+      - /mnt/user/appdata/mc-cars/data/n8n:/home/node/.n8n
+    ports:
+      - "55590:5678"
+    networks: [mccars]
+    logging: { driver: json-file, options: { max-size: "10m", max-file: "3" } }