feat: winget 安装 fnm 后智能搜索 PATH 避免重启终端

winget 安装 fnm 后 PATH 可能未立即生效，新增 Find-FnmPath
在 WinGet Links/Packages、.fnm、LOCALAPPDATA 等常见位置搜索
fnm.exe 并自动加入当前会话 PATH，无需重启终端。

GeminiCLI/setup-gemini.ps1

@@ -92,6 +92,25 @@ function Get-NodeVersion {
     return $null
 }
 
+# ========== fnm PATH 搜索 ==========
+function Find-FnmPath {
+    $searchPaths = @(
+        "$env:LOCALAPPDATA\Microsoft\WinGet\Links",
+        "$env:LOCALAPPDATA\Microsoft\WinGet\Packages\Schniz.fnm_*",
+        "$env:USERPROFILE\.fnm",
+        "$env:LOCALAPPDATA\fnm",
+        "$env:ProgramFiles\fnm"
+    )
+    foreach ($pattern in $searchPaths) {
+        $resolved = Resolve-Path $pattern -ErrorAction SilentlyContinue
+        foreach ($dir in $resolved) {
+            $fnmExe = Get-ChildItem -Path $dir.Path -Filter "fnm.exe" -Recurse -Depth 2 -ErrorAction SilentlyContinue | Select-Object -First 1
+            if ($fnmExe) { return $fnmExe.DirectoryName }
+        }
+    }
+    return $null
+}
+
 function Install-Fnm {
     Write-Host ""
     Write-Info "正在安装 fnm (Fast Node Manager)..."
@@ -108,6 +127,15 @@ function Install-Fnm {
 
         Refresh-Path
 
+        if (-not (Test-Command "fnm")) {
+            Write-Info "正在搜索 fnm 安装位置..."
+            $fnmDir = Find-FnmPath
+            if ($fnmDir) {
+                Write-Info "在 $fnmDir 找到 fnm"
+                $env:Path = "$fnmDir;$env:Path"
+            }
+        }
+
         if (Test-Command "fnm") {
             Write-Success "fnm 安装成功!"
             $fnmEnv = & fnm env --use-on-cd 2>$null
@@ -117,8 +145,7 @@ function Install-Fnm {
             return $true
         }
         else {
-            Write-Warning "fnm 可能已安装，但需要重新打开终端才能生效"
-            Write-Info "请重新打开 PowerShell 后再运行此脚本"
+            Write-Warning "fnm 安装后未能在 PATH 中找到，请重新打开终端后再运行此脚本"
             return $false
         }
     }