ci: Ajout du workflow Gitea pour le tag 'ext'

- Création de .gitea/workflows/build-ext.yml
- Workflow déclenché sur push du tag 'ext'
- Build et push de l'image sdk_storage:ext
- Configuration SSH et Docker registry

.gitea/workflows/build-ext.yml

@@ -0,0 +1,60 @@
+name: build-and-push-ext
+
+on:
+  push:
+    tags:
+      - ext
+
+jobs:
+  build_push:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Prepare SSH agent (optional)
+        shell: bash
+        run: |
+          set -euo pipefail
+          eval "$(ssh-agent -s)"
+          if [ -n "${{ secrets.SSH_PRIVATE_KEY || '' }}" ]; then
+            echo "${{ secrets.SSH_PRIVATE_KEY }}" | tr -d '\r' | ssh-add - >/dev/null 2>&1 || true
+          fi
+          mkdir -p ~/.ssh
+          ssh-keyscan git.4nkweb.com >> ~/.ssh/known_hosts 2>/dev/null || true
+          echo "SSH agent ready: $SSH_AUTH_SOCK"
+          # Rendre l'agent dispo aux steps suivants
+          echo "SSH_AUTH_SOCK=$SSH_AUTH_SOCK" >> "$GITHUB_ENV"
+          echo "SSH_AGENT_PID=$SSH_AGENT_PID" >> "$GITHUB_ENV"
+
+      - name: Docker login (git.4nkweb.com)
+        shell: bash
+        env:
+          REG_USER: ${{ secrets.USER }}
+          REG_TOKEN: ${{ secrets.TOKEN }}
+        run: |
+          set -euo pipefail
+          echo "$REG_TOKEN" | docker login git.4nkweb.com -u "$REG_USER" --password-stdin
+
+      - name: Build image (target ext)
+        shell: bash
+        env:
+          DOCKER_BUILDKIT: "1"
+        run: |
+          set -euo pipefail
+          if [ -n "${SSH_AUTH_SOCK:-}" ]; then
+            docker build --ssh default \
+              -t git.4nkweb.com/4nk/sdk_storage:ext \
+              -f Dockerfile .
+          else
+            echo "SSH_AUTH_SOCK non défini: l'agent SSH n'est pas disponible. Assurez-vous de définir secrets.SSH_PRIVATE_KEY."
+            exit 1
+          fi
+
+      - name: Push image
+        shell: bash
+        run: |
+          set -euo pipefail
+          docker push git.4nkweb.com/4nk/sdk_storage:ext