ci: 运行环境自愈预置 + 发版任务串行 + 删 ci.yml/暂停备份

- 新增 scripts/ci/provision-{mac,windows}.sh：幂等预置，按 Flutter 版本
  stamp 短路，pipeline 首跑自动 precache + 预热缓存，运行时不再下载 engine
- scripts/ci/_env.sh：抽出共用镜像 env，compile 脚本统一 source
- deploy.yml：build-macos needs build-linux-web，同一 mac runner 串行
  执行，避免排队超时；各 build job 加 Provision 前置步骤
- 删除 .gitea/workflows/ci.yml
- backup.yml：暂停定时备份（保留 workflow_dispatch 手动触发）

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/deploy.yml

@@ -16,6 +16,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Provision (idempotent — auto-runs if host not initialized)
+        run: sh scripts/ci/provision-mac.sh
+
       - name: Compile (Linux backend + Flutter Web)
         run: sh scripts/ci/compile.sh "${{ gitea.ref_name }}"
 
@@ -26,6 +29,9 @@ jobs:
           path: dist/
 
   build-macos:
+    # Same physical runner as build-linux-web (label: mac, capacity 1). Run them
+    # serially via needs so the second job doesn't sit queued and time out.
+    needs: build-linux-web
     runs-on: mac
     env:
       PUB_HOSTED_URL: https://pub.flutter-io.cn
@@ -34,6 +40,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Provision (idempotent — auto-runs if host not initialized)
+        run: sh scripts/ci/provision-mac.sh
+
       - name: Compile (Flutter macOS)
         run: sh scripts/ci/compile-macos.sh "${{ gitea.ref_name }}"
 
@@ -53,6 +62,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - name: Provision (idempotent — auto-runs if host not initialized)
+        shell: bash
+        run: sh scripts/ci/provision-windows.sh
+
       - name: Compile (Flutter Windows)
         shell: bash
         run: sh scripts/ci/compile-windows.sh "${{ gitea.ref_name }}"