* fix: Refactor CORS middleware to consistently apply the `Vary: Origin` header when a configuration exists and streamline request processing logic.
* fix: Add Vary: Origin header to CORS OPTIONS responses and refactor request handling for clarity and correctness.
* fix: update CORS middleware tests to correctly parse and check for 'Origin' in Vary header.
* refactor: extract `hasVaryOrigin` helper function to simplify Vary header checks in tests.
* test: Remove `Vary: Origin` header from CORS test expectations.
* refactor: consolidate CORS request handling into a new `processCORS` method using a `next` callback.
Fix S3 CORS for non-existent buckets
Enable fallback to global CORS configuration when a bucket is not found (s3err.ErrNoSuchBucket). This ensures consistent CORS behavior and prevents information disclosure.
* add fallback for cors
* refactor
* expose aws headers
* add fallback to test
* refactor
* Only falls back to global config when there's explicitly no bucket-level config.
* fmt
* Update s3_cors_http_test.go
* refactoring
