ci(devops): Windows runner 将 shell 钉到 Git for Windows 自带 bash 绝对路径

Git 安装包默认只把 git.exe 加入 PATH（Git\cmd），不含 bash.exe（Git\bin），
导致 act_runner 解析 `shell: bash` 时报「Cannot find: bash in PATH」。
改用 GitHub Actions 官方等价写法，绕过 PATH 查找：
  C:\Program Files\Git\bin\bash.exe --noprofile --norc -eo pipefail {0}
（bin\bash.exe 包装器会注入 /usr/bin，使脚本内 sh/powershell 可解析）

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

.gitea/workflows/build-windows.yml

@@ -28,11 +28,11 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Provision (idempotent — auto-runs if host not initialized)
-        shell: bash
+        shell: 'C:\Program Files\Git\bin\bash.exe --noprofile --norc -eo pipefail {0}'
         run: sh scripts/ci/provision-windows.sh
 
       - name: Compile (Flutter Windows)
-        shell: bash
+        shell: 'C:\Program Files\Git\bin\bash.exe --noprofile --norc -eo pipefail {0}'
         run: sh scripts/ci/compile-windows.sh "${{ inputs.ver || 'v1.0.4' }}"
 
       - name: Upload windows artifact

.gitea/workflows/deploy-client.yml

@@ -122,11 +122,11 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Provision (idempotent — auto-runs if host not initialized)
-        shell: bash
+        shell: 'C:\Program Files\Git\bin\bash.exe --noprofile --norc -eo pipefail {0}'
         run: sh scripts/ci/provision-windows.sh
 
       - name: Compile (Flutter Windows)
-        shell: bash
+        shell: 'C:\Program Files\Git\bin\bash.exe --noprofile --norc -eo pipefail {0}'
         run: sh scripts/ci/compile-windows.sh "${{ gitea.ref_name }}"
 
       - name: Upload windows artifacts