- Add TypeAnnotation AST node for type annotations
- Add ClassField dataclass for typed class fields
- Extend Parameter, FunctionDecl, Assignment with type_annotation field
- Add type parsing: parse_type(), parse_type_annotation(), parse_function_type()
- Support types: string, int, float, bool, any, void, T[], dict[K,V], classes, (A) => B
- Add type checking at compile time with configurable error handling
- Add --no-type-check and --warn-types CLI flags
- Fix callback variable calls (prioritize callback_vars, use $() capture)
- Document closure limitation (lambdas can't capture outer variables)
- Add 28 new tests for typing and callbacks (279 total)