ci: update deploy.json on web after each release via docker exec

Adds docker-cli to build container (docker socket passed through by runner)
and writes sha + timestamp to xetup-web container after successful release.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.forgejo/workflows/release.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Setup
         working-directory: /
         run: |
-          apk add --no-cache git curl jq mingw-w64-gcc
+          apk add --no-cache git curl jq mingw-w64-gcc docker-cli
           git clone --depth=1 \
             "http://x9:${{ secrets.FORGEJO_TOKEN }}@xetup-forgejo:3000/${{ github.repository }}.git" \
             /repo
@@ -80,3 +80,11 @@ jobs:
             --data-binary @xetup.exe
 
           echo "Released xetup.exe (commit ${SHORT})"
+
+      - name: Update deploy.json
+        run: |
+          SHORT=$(echo "${{ github.sha }}" | cut -c1-7)
+          TS=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+          docker exec xetup-web sh -c \
+            "echo '{\"sha\":\"${SHORT}\",\"ts\":\"${TS}\"}' > /usr/share/nginx/html/data/deploy.json"
+          echo "deploy.json updated: ${SHORT} at ${TS}"