refactor(frontend): Move parser to ast folder, use TokenValue::Eof to replace None

src/ast/mod.rs

@@ -1,2 +1,3 @@
 pub mod graph;
+pub mod parser;
 pub mod types;

src/ast/types.rs

@@ -1,4 +1,4 @@
-use crate::{diagnostic::span::Span, frontend::types::{Token, TokenValue, TypeIdent}};
+use crate::{diagnostic::span::Span, lexer::types::{TokenValue, TypeIdent}};
 use std::fmt;
 
 pub struct CompileUnit {