Add purity to LocalInfo and initialize in binder

The `LocalInfo` struct now includes a `purity` field to track the purity
of local variables and function arguments. This is initialized to
`Purity::Impure` for local variables and arguments within functions and
when registering native functions. Additionally, the `Environment`
struct is updated to include `root_scopes` and `root_slot_count` to
support parallel mode compilation by populating the root scope with
initial function and native function information.

src/ast/compiler/binder.rs

@@ -3,7 +3,7 @@ use crate::ast::compiler::bound_nodes::{
 };
 use crate::ast::diagnostics::Diagnostics;
 use crate::ast::nodes::{Node, Symbol, UntypedKind};
-use crate::ast::types::{Identity, StaticType};
+use crate::ast::types::{Identity, StaticType, Purity};
 use std::cell::RefCell;
 use std::collections::HashMap;
 use std::rc::Rc;
@@ -13,6 +13,7 @@ pub struct LocalInfo {
     pub addr: Address,
     pub identity: Identity,
     pub _ty: StaticType,
+    pub purity: Purity,
 }
 
 #[derive(Debug, Clone)]
@@ -69,6 +70,7 @@ impl FunctionCompiler {
                 addr: Address::Local(slot),
                 identity,
                 _ty: StaticType::Any,
+                purity: Purity::Impure,
             },
         );
         self.slot_count += 1;
@@ -191,6 +193,7 @@ impl Binder {
                         addr,
                         identity,
                         _ty: StaticType::Any,
+                        purity: Purity::Impure,
                     },
                 );
                 return Some(addr);