ci: optimize docker image tag strategy

- develop branch: use fixed 'dev' tag (overwrite, no accumulation)
- main branch: use 'latest' + commit sha tags
- release tags (v*): use version number as tag
- PR/other branches: skip docker push

.gitea/workflows/ci.yml

@@ -3,8 +3,10 @@ name: CI Pipeline
 on:
   push:
     branches: [main, develop]
+    tags:
+      - 'v*'
   pull_request:
-    branches: [main]
+    branches: [main, develop]
 
 env:
   REGISTRY: git.xiaoxiajianji.com
@@ -50,7 +52,12 @@ jobs:
     name: Build & Push Docker Image
     runs-on: ubuntu-latest
     needs: lint-and-build
-    if: github.ref == 'refs/heads/main'
+    # 仅在 main/develop 分支和 release tag 上构建推送镜像
+    # PR 和其他分支不推送镜像，避免产生多余 tag
+    if: |
+      github.ref == 'refs/heads/main' ||
+      github.ref == 'refs/heads/develop' ||
+      startsWith(github.ref, 'refs/tags/v')
     steps:
       - name: Checkout code
         uses: actions/checkout@v4
@@ -71,13 +78,37 @@ jobs:
           username: ${{ gitea.actor }}
           password: ${{ secrets.GITEA_TOKEN }}
 
+      - name: Set image tags based on ref
+        id: tags
+        run: |
+          IMAGE="${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}"
+          case "${{ github.ref }}" in
+            refs/heads/main)
+              # main 分支：latest + commit sha（版本号用 sha）
+              TAGS="${IMAGE}:latest,${IMAGE}:${{ gitea.sha }}"
+              ;;
+            refs/heads/develop)
+              # develop 分支：固定 dev tag（覆盖推送，不堆积）
+              TAGS="${IMAGE}:dev"
+              ;;
+            refs/tags/v*)
+              # release tag：用版本号作为 tag
+              VERSION="${GITHUB_REF_NAME}"
+              TAGS="${IMAGE}:${VERSION}"
+              ;;
+            *)
+              echo "::warning::No push for ref ${{ github.ref }}"
+              TAGS=""
+              ;;
+          esac
+          echo "tags=${TAGS}"
+          echo "tags=${TAGS}" >> $GITHUB_OUTPUT
+
       - name: Build and push
         uses: actions/build-push-action@v6
         with:
           context: .
           push: true
-          tags: |
-            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
-            ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ gitea.sha }}
+          tags: ${{ steps.tags.outputs.tags }}
           cache-from: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:buildcache
           cache-to: type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:buildcache,mode=max