feat: add vikunja stack (Coolify-ready)

- pull_policy: always on vikunja service
- hardcoded bind mounts: /opt/vikunja/{postgres,files}
- port hardcoded in label: 3456 (Gotcha 6)
- removed Portainer Traefik router labels
- vikunja_internal: driver bridge (no fixed name)
- proxy: external: true

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

vikunja/docker-compose.yml

@@ -0,0 +1,57 @@
+services:
+  vikunja-db:
+    image: postgres:17-alpine
+    container_name: vikunja-db
+    restart: unless-stopped
+    environment:
+      TZ: ${TZ}
+      POSTGRES_DB: ${VIKUNJA_DB_NAME}
+      POSTGRES_USER: ${VIKUNJA_DB_USER}
+      POSTGRES_PASSWORD: ${VIKUNJA_DB_PASSWORD}
+    volumes:
+      - /opt/vikunja/postgres:/var/lib/postgresql/data:Z
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${VIKUNJA_DB_USER} -d ${VIKUNJA_DB_NAME}"]
+      interval: 10s
+      timeout: 5s
+      retries: 10
+      start_period: 20s
+    networks:
+      - vikunja_internal
+
+  vikunja:
+    image: vikunja/vikunja:latest
+    pull_policy: always
+    container_name: vikunja
+    restart: unless-stopped
+    user: "1000:1000"
+    depends_on:
+      vikunja-db:
+        condition: service_healthy
+    environment:
+      TZ: ${TZ}
+      VIKUNJA_SERVICE_PUBLICURL: https://${VIKUNJA_DOMAIN}/
+      VIKUNJA_SERVICE_JWTSECRET: ${VIKUNJA_JWT_SECRET}
+      VIKUNJA_DATABASE_TYPE: postgres
+      VIKUNJA_DATABASE_HOST: vikunja-db
+      VIKUNJA_DATABASE_PORT: 5432
+      VIKUNJA_DATABASE_DATABASE: ${VIKUNJA_DB_NAME}
+      VIKUNJA_DATABASE_USER: ${VIKUNJA_DB_USER}
+      VIKUNJA_DATABASE_PASSWORD: ${VIKUNJA_DB_PASSWORD}
+      VIKUNJA_SERVICE_ENABLECALDAV: "true"
+      VIKUNJA_MAILER_ENABLED: "false"
+      VIKUNJA_SERVICE_ENABLEEMAILREMINDERS: "false"
+      VIKUNJA_SERVICE_ENABLEREGISTRATION: "false"
+    volumes:
+      - /opt/vikunja/files:/app/vikunja/files:Z
+    networks:
+      - vikunja_internal
+      - proxy
+    labels:
+      traefik.http.services.vikunja.loadbalancer.server.port: "3456"
+
+networks:
+  vikunja_internal:
+    driver: bridge
+  proxy:
+    external: true

vikunja/stack.env

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+TZ=Europe/Madrid
+VIKUNJA_DOMAIN=vikunja.sherlockhomeless.net
+VIKUNJA_DB_NAME=vikunja
+VIKUNJA_DB_USER=vikunja
+VIKUNJA_DB_PASSWORD=CAMBIAME_db_super_largo_y_unico
+VIKUNJA_JWT_SECRET=CAMBIAME_jwt_super_largo_y_unico_y_muy_largo