- refactor: replace inline AppError literals with model.New*Error
constructors in service and handler layers
- feat: PromoteStaged falls back to copy/delete when os.Rename returns
EXDEV (cross-device link)
- fix: upload error messages no longer leak internal multipart field
names or parser implementation details
- fix: upload size violations are converted to domain error
ErrUploadTooLarge at the handler boundary
- fix: download logs error and size mismatch when io.Copy fails or
writes fewer bytes than expected
- test: add tests for field name leak prevention, parser error
sanitization, read errors after response start, and EXDEV fallback
ld
28e17a5b08