- Migrated all 11 functions in expression-api.ts to return Promise<ApiResponse<T>>
- Implemented manual response handling following person-api pattern
- Properly unwrap nested API responses and re-wrap in ApiResponse
- Updated all 16 call sites across 4 files with proper error handling
- Fixed type annotations (ChatInfo) in expression.tsx
- Build passes successfully with no TypeScript errors
- Follows AGENTS.md import conventions and Wave 2 constraints
- All HTTP and API-level errors handled consistently via ApiResponse
