Add MCP server to AST tool

Integrates the MCP server functionality into the AST tool binary. This
allows the tool to act as a server for LLM integration, enabling
communication over stdio. The server can list available bindings and
execute scripts.

src/ast/environment.rs

@@ -600,6 +600,19 @@ impl Environment {
     }
 
 
+    /// Returns the names of all bindings registered in the fixed RTL scope.
+    /// Useful for introspection (e.g., MCP server listing available built-ins).
+    pub fn list_bindings(&self) -> Vec<String> {
+        let root_scopes = self.root_scopes.borrow();
+        let mut names: Vec<String> = root_scopes[0]
+            .locals
+            .keys()
+            .map(|sym| sym.name.to_string())
+            .collect();
+        names.sort();
+        names
+    }
+
     pub fn dump_ast(&self, source: &str) -> Result<String, String> {
         self.preload_dependencies(source, None)?;
         let compiled = self.compile(source).into_result()?;

src/ast/mod.rs

@@ -3,6 +3,7 @@ pub mod compiler;
 pub mod diagnostics;
 pub mod environment;
 pub mod lexer;
+pub mod mcp_server;
 pub mod nodes;
 pub mod parser;
 pub mod rtl;

src/bin/ast.rs

@@ -39,10 +39,22 @@ struct Cli {
     /// Disable optimization
     #[arg(long)]
     no_opt: bool,
+
+    /// Start MCP server (stdio transport, for LLM integration)
+    #[arg(long)]
+    mcp: bool,
 }
 
 fn main() {
     let cli = Cli::parse();
+
+    if cli.mcp {
+        if let Err(e) = myc::ast::mcp_server::run() {
+            eprintln!("MCP server error: {}", e);
+            std::process::exit(1);
+        }
+        return;
+    }
     let mut env = Environment::new();
     env.optimization = !cli.no_opt;