- Add interface field display in initial context: interface User { id: string, name: string }
- Add type alias definition display: type UserId = string
- Support readonly fields, extends, union/intersection types
- Add definition field to TypeAliasInfo in FileAST
- Update ASTParser to extract type alias definitions
- Add formatInterfaceSignature() and formatTypeAliasSignature() helpers
- Truncate long type definitions at 80 characters
- Translate ROADMAP.md from Russian to English
- Add 18 new tests for interface fields and type aliases
