Introduces the lexer and parser modules, enabling the conversion of
source code into an Abstract Syntax Tree (AST).
This includes:
- Defining token kinds and structures.
- Implementing lexer logic to tokenize input.
- Defining AST node kinds and structures.
- Implementing parser logic to construct the AST from tokens.
- Adding support for basic expressions, lists, keywords, and
identifiers.
- Adding the `lazy_static` dependency for keyword interning.
- Refactoring `Value::Nil` to `Value::Void`.
Sets up the basic structure for the compiler GUI application using
eframe.
This includes the main application loop, a default UI layout with a
source code editor and an output log panel, and the foundational AST
(Abstract Syntax Tree) definitions for types, nodes, and an evaluation
mechanism.