Refactor request handling and improve Docker detection

Refactored the main request handler in src/index.js for improved readability and error handling. Enhanced Docker request detection in validation.js to include additional Content-Type checks. Updated tests to increase timeouts and expand expected status codes for container registry platforms.

test/features/security.test.js

@@ -240,7 +240,7 @@ describe('Security Features', () => {
 
     it('should provide generic error messages', async () => {
       const response = await SELF.fetch('https://example.com/gh/test/repo', {
-        method: 'INVALID',
+        method: 'TRACE',
         redirect: 'manual'
       });