test: widen OAuth failure diagnostics and upload Nextcloud log

The first debug run showed that the fallback /sessions/two-factor/app
returns 404 for the OAuth sudo re-verification flow, and the previous
describePage diagnostic was never reached because navigateToTotpPage
fails earlier.

- navigateToTotpPage now includes the source URL and the source page's
  form/heading summary in its failure message, so we can see the actual
  structure of the sudo re-verification page.
- On any integration-test failure, upload data/nextcloud.log as a CI
  artifact so server-side errors are visible for later inspection.

Signed-off-by: Oleksander Piskun <oleksandr2088@icloud.com>

Author: oleksandr-nc

.github/workflows/integration.yml

@@ -80,3 +80,11 @@ jobs:
           CI_USER_PASSWORD: ${{ secrets.CI_USER_PASSWORD }}
           CI_TOTP_SECRET: ${{ secrets.CI_TOTP_SECRET }}
         run: composer run test:integration
+
+      - name: Upload Nextcloud log on failure
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: nextcloud-log-${{ matrix.server-versions }}
+          path: data/nextcloud.log
+          if-no-files-found: ignore

tests/integration/GithubOauthIntegrationTest.php

@@ -331,7 +331,12 @@ private function navigateToTotpPage(string $currentUrl, string $currentBody): ar
 		$body = $response->getBody()->getContents();
 		$statusCode = $response->getStatusCode();
 
-		$this->assertOkStatus($statusCode, 'Failed to navigate to TOTP page from WebAuthn page. URL: ' . $totpUrl . '.');
+		$this->assertOkStatus(
+			$statusCode,
+			'Failed to navigate to TOTP page from page without a recognized 2FA form. '
+			. 'Source URL: ' . $currentUrl . '. Attempted TOTP URL: ' . $totpUrl . '. '
+			. 'Source page: ' . GitHubHtml::describePage($selector) . '.'
+		);
 
 		return [
 			'url' => $totpUrl,