ci: docker_tag=ext sanitize tag extraction; add .gitea workflow; push image to ext

.gitea/workflows/docker-build.yml

@@ -0,0 +1,44 @@
+name: Docker Build and Push (ext)
+
+on:
+  push:
+    branches:
+      - ext
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Derive DOCKER_TAG from commit message or fallback
+        id: tag
+        run: |
+          msg=$(git log -1 --pretty=%B | tr -d '\r')
+          tag=$(printf '%s' "$msg" | sed -n 's/.*docker_tag=\([A-Za-z0-9._-]\+\).*/\1/p' | head -n1)
+          if [ -z "$tag" ]; then tag=dev-test; fi
+          tag=$(printf '%s' "$tag" | tr -d '[:space:]')
+          echo "DOCKER_TAG=$tag" >> $GITHUB_ENV
+          echo "tag=$tag" >> $GITHUB_OUTPUT
+
+      - name: Log in to registry
+        uses: docker/login-action@v3
+        with:
+          registry: git.4nkweb.com
+          username: ${{ secrets.USER }}
+          password: ${{ secrets.TOKEN }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          platforms: linux/amd64
+          push: true
+          tags: |
+            git.4nkweb.com/4nk/ihm_client:${{ env.DOCKER_TAG }}
+
+