fix: detect OAuth requirement from unexpected content-type responses

.github/workflows/e2e-desktop.yml

@@ -127,6 +127,26 @@ jobs:
             xvfb-run --auto-servernum pnpm test:e2e
           '
 
+      - name: Install matching EdgeDriver (Windows)
+        if: matrix.os == 'windows-latest'
+        shell: pwsh
+        run: |
+          # Tauri uses the WebView2 runtime, not Edge directly.
+          # msedgedriver must match the WebView2 runtime version, not the Edge browser version.
+          $wv2Key = 'HKLM:\SOFTWARE\WOW6432Node\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}'
+          if (-not (Test-Path $wv2Key)) { $wv2Key = 'HKLM:\SOFTWARE\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}' }
+          $wv2Version = (Get-ItemProperty $wv2Key).pv
+          Write-Host "WebView2 runtime version: $wv2Version"
+          $driverUrl = "https://msedgewebdriverstorage.blob.core.windows.net/edgewebdriver/$wv2Version/edgedriver_win64.zip"
+          $zipPath = "$env:TEMP\edgedriver.zip"
+          $extractDir = "$env:TEMP\edgedriver"
+          Invoke-WebRequest -Uri $driverUrl -OutFile $zipPath
+          Expand-Archive -Path $zipPath -DestinationPath $extractDir -Force
+          $driverDir = "$extractDir\edgedriver_win64"
+          if (-not (Test-Path "$driverDir\msedgedriver.exe")) { $driverDir = $extractDir }
+          Write-Host "EdgeDriver path: $driverDir"
+          echo "$driverDir" | Out-File -Append -Encoding utf8 $env:GITHUB_PATH
+
       - name: Run desktop E2E tests (Windows)
         if: matrix.os == 'windows-latest'
         run: pnpm test:e2e

crates/mcpmux-gateway/src/pool/transport/http.rs

@@ -94,6 +94,7 @@ impl HttpTransport {
             "access token",
             "missing or invalid",
             "bearer",
+            "unexpected content type",
         ];
         oauth_indicators.iter().any(|s| error_lower.contains(s))
     }
@@ -845,6 +846,13 @@ mod tests {
         assert!(HttpTransport::requires_oauth("transport channel closed"));
     }
 
+    #[test]
+    fn test_requires_oauth_unexpected_content_type() {
+        assert!(HttpTransport::requires_oauth(
+            "Unexpected content type: Some(\"text/plain;charset=UTF-8\")"
+        ));
+    }
+
     #[test]
     fn test_requires_oauth_false_for_unrelated() {
         assert!(!HttpTransport::requires_oauth("connection refused"));