chore: initialize NexaCore compiler workspace with basic frontend and CLI

Add initial project structure for NexaCore programming language compiler:
- Create Cargo workspace with 4 crates (cli, driver, frontend, runtime)
- Add lexer with indentation-based tokenization and keyword support
- Add parser for modules, functions, structs, and basic expressions
- Implement CLI with build command and placeholder subcommands
- Add driver crate to orchestrate compilation pipeline
- Include .gitignore for Rust build

crates/nxc-driver/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "nxc-driver"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+authors.workspace = true
+
+[lib]
+path = "src/lib.rs"
+
+[dependencies]
+nxc-frontend = { path = "../nxc-frontend" }
+

crates/nxc-driver/src/lib.rs

@@ -0,0 +1,41 @@
+use std::fs;
+use std::path::Path;
+
+use nxc_frontend::{Lexer, Module, ParseError, Parser, Token};
+
+#[derive(Debug)]
+pub struct CompileResult {
+    pub tokens: Vec<Token>,
+    pub module: Module,
+}
+
+#[derive(Debug)]
+pub enum CompileError {
+    Io(std::io::Error),
+    Parse(ParseError),
+}
+
+impl From<std::io::Error> for CompileError {
+    fn from(value: std::io::Error) -> Self {
+        Self::Io(value)
+    }
+}
+
+impl From<ParseError> for CompileError {
+    fn from(value: ParseError) -> Self {
+        Self::Parse(value)
+    }
+}
+
+pub fn compile_file(path: impl AsRef<Path>) -> Result<CompileResult, CompileError> {
+    let source = fs::read_to_string(path)?;
+    compile_source(&source)
+}
+
+pub fn compile_source(source: &str) -> Result<CompileResult, CompileError> {
+    let tokens = Lexer::new(source).tokenize();
+    let mut parser = Parser::new(tokens.clone());
+    let module = parser.parse_module()?;
+    Ok(CompileResult { tokens, module })
+}
+