fix(install): add network timeouts to install script downloads

The GitHub API and binary download calls in `install_binary()` (`scripts/install.sh`) and `Install-Binary` (`scripts/install.ps1`) could hang indefinitely on stalled connections. Added curl `--connect-timeout`/`--max-time` to the release metadata calls and `--connect-timeout`/`--speed-limit`/`--speed-time` to the binary download, plus `-TimeoutSec` to the PowerShell `Invoke-RestMethod`/`Invoke-WebRequest` calls. Verified `bash -n scripts/install.sh` passes; no TypeScript typecheck is affected.

Closes #4253

scripts/install.ps1

@@ -239,13 +239,13 @@ function Install-Binary {
     if ($Ref) {
         Write-Host "Fetching release $Ref..."
         try {
-            $Release = Invoke-RestMethod -Uri "https://api.github.com/repos/$Repo/releases/tags/$Ref"
+            $Release = Invoke-RestMethod -Uri "https://api.github.com/repos/$Repo/releases/tags/$Ref" -TimeoutSec 60
         } catch {
             throw "Release tag not found: $Ref`nFor branch/commit installs, use -Source with -Ref."
         }
     } else {
         Write-Host "Fetching latest release..."
-        $Release = Invoke-RestMethod -Uri "https://api.github.com/repos/$Repo/releases/latest"
+        $Release = Invoke-RestMethod -Uri "https://api.github.com/repos/$Repo/releases/latest" -TimeoutSec 60
     }
 
     $Latest = $Release.tag_name
@@ -260,7 +260,7 @@ function Install-Binary {
     $BinaryUrl = "https://github.com/$Repo/releases/download/$Latest/$BinaryName"
     Write-Host "Downloading $BinaryName..."
     $OutPath = Join-Path $InstallDir "omp.exe"
-    Invoke-WebRequest -Uri $BinaryUrl -OutFile $OutPath
+    Invoke-WebRequest -Uri $BinaryUrl -OutFile $OutPath -TimeoutSec 900
 
     Write-Host ""
     Write-Host "✓ Installed omp to $OutPath" -ForegroundColor Green