feat(deploy): build + serve worker and admin as static nginx images

- per-app Dockerfiles (vite build → nginx) + SPA nginx.conf
- Gitea workflow pushes 3 images; frontends bake VITE_API_URL
- docker-compose.prod.yml (registry images, solelog_network) + .env.prod.example
- docker-compose.yml runs the full stack locally; add .dockerignore

.dockerignore

@@ -0,0 +1,36 @@
+# Keep Docker build contexts small and reproducible.
+# (CI checks out only git-tracked files, but local `docker compose build` would
+#  otherwise ship node_modules/dist — hundreds of MB — into the context.)
+
+# dependencies
+node_modules
+**/node_modules
+.pnp.*
+
+# build output / incremental caches
+**/dist
+out
+**/*.tsbuildinfo
+**/coverage
+
+# vcs / ci
+.git
+.gitignore
+.gitea
+
+# env & secrets (API URL is passed as a build-arg, never copied in)
+**/.env
+**/.env.*
+!**/.env.example
+
+# local API data (SQLite)
+apps/api/data
+apps/api/.tmp
+
+# editor / os cruft
+.idea
+.DS_Store
+
+# test artefacts
+playwright-report
+test-results