feat(deploy): add Gitea registry publish script and pull-based compose

- scripts/publish.ps1: build image and push to git.azuze.fr/kawa/imptune
- docker-compose.yml: reference published image (build kept for local builds)
- docker-compose.override.yml: gitignored live-reload dev config
- add .gitignore (override + Python/data artifacts)
- README: document dev vs published-image run and publishing

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -1,14 +1,17 @@
 services:
   imptune:
+    # Pull the published image by default (docker compose pull / up).
+    # `build` is kept so `docker compose build` still produces a correctly
+    # tagged local image; scripts/publish.ps1 pushes it to the registry.
+    image: git.azuze.fr/kawa/imptune:latest
     build: .
     ports:
       - "8000:8000"
     volumes:
       - imptune_data:/data
-      - ./imptune:/app/imptune
     restart: unless-stopped
     environment:
       - DATA_DIR=/data
 
 volumes:
-  imptune_data:
+  imptune_data: