[rust-compiler] Fix OXC frontend compilation and e2e test failures

Fix three issues in the OXC frontend that caused 1513/1717 e2e test failures:

1. Two-step JSON deserialization to handle duplicate "type" keys (matching SWC approach)
2. Force module source type for .js files (matching SWC's parse_file_as_module behavior)
3. Comment preservation by re-parsing source and attaching comments to compiled output

OXC e2e results: 204 → 606 passing.