feat(CI): 添加 NuGet 安装脚本并优化 CI 流程

添加三个 NuGet 安装脚本（批处理和 PowerShell），支持直接下载和通过 Chocolatey 安装
修改 CI 工作流，优先使用 Chocolatey 安装 NuGet 并更新 PATH 路径

.gitea/workflows/docker.yml

@@ -238,26 +238,27 @@ jobs:
         $nugetPath = Get-Command nuget -ErrorAction SilentlyContinue
         if ($nugetPath) {
           Write-Host "NuGet already installed: $($nugetPath.Source)"
+          $nugetVersion = nuget help | Select-String -Pattern "NuGet Version" | Select-Object -First 1
+          Write-Host "NuGet version: $nugetVersion"
           return
         }
         
-        # Download NuGet CLI
-        Write-Host "Downloading NuGet CLI..."
-        try {
-          Invoke-WebRequest -Uri "https://dist.nuget.org/win-x86-commandline/latest/nuget.exe" -OutFile "C:\nuget.exe" -TimeoutSec 120
-        } catch {
-          Write-Host "Download failed, trying alternative..."
-          # Try alternative download
-          Invoke-WebRequest -Uri "https://dist.nuget.org/win-x86-commandline/v6.7.0/nuget.exe" -OutFile "C:\nuget.exe" -TimeoutSec 120
-        }
+        # Use Chocolatey to install NuGet (proven to work)
+        Write-Host "Installing NuGet via Chocolatey..."
+        choco install nuget.commandline -y
         
-        # Add to PATH
-        $env:PATH = "C:\;$env:PATH"
-        Add-Content -Path $env:GITHUB_PATH -Value "C:\"
+        # Update PATH to include Chocolatey
+        $env:PATH = "C:\ProgramData\chocolatey\bin;$env:PATH"
+        Add-Content -Path $env:GITHUB_PATH -Value "C:\ProgramData\chocolatey\bin"
         
         # Verify installation
-        $nugetVersion = C:\nuget.exe help | Select-String -Pattern "NuGet Version" | Select-Object -First 1
-        Write-Host "NuGet installed: $nugetVersion"
+        if (Get-Command nuget -ErrorAction SilentlyContinue) {
+          Write-Host "NuGet installed successfully via Chocolatey"
+          $nugetVersion = nuget help | Select-String -Pattern "NuGet Version" | Select-Object -First 1
+          Write-Host "NuGet version: $nugetVersion"
+        } else {
+          Write-Host "WARNING: NuGet installation may have failed, but continuing..."
+        }
 
     - name: Fix long paths
       shell: powershell
@@ -293,13 +294,13 @@ jobs:
     - name: Build Windows Debug
       shell: powershell
       run: |
-        $env:PATH = "C:\flutter\bin;C:\;$env:PATH"
+        $env:PATH = "C:\flutter\bin;C:\ProgramData\chocolatey\bin;$env:PATH"
         flutter build windows
 
     - name: Build Windows Release
       shell: powershell
       run: |
-        $env:PATH = "C:\flutter\bin;C:\;$env:PATH"
+        $env:PATH = "C:\flutter\bin;C:\ProgramData\chocolatey\bin;$env:PATH"
         flutter build windows --release
 
     - name: Upload Debug build artifacts