test: add QOI codec unit tests and E2E GUI format support tests

- QOI codec: 16 tests covering encode/decode round-trips, error handling, fixture validation
- E2E: 28 tests for format upload/resize, convert new outputs, dropdown verification,
  HEIC-to-JPG flow, and exotic format upload acceptance

apps/api/src/lib/format-decoders.ts

@@ -85,7 +85,6 @@ export async function decodeToSharpCompat(
     case "pgm":
     case "pbm":
       return decodeNetpbm(buffer, format);
-      return decodeQoi(buffer);
     default:
       return buffer;
   }