### What problem does this PR solve?
Fixes web API behavior mismatches that caused test failures by
normalizing error responses, tightening validations, correcting error
messages, and closing upload file handles.
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
### What problem does this PR solve?
Move memory and message apis to /api, and add sdk support.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
