Add type aliases for registries

Introduces `GlobalFunctionRegistry` and `GlobalAnalyzedRegistry` type
aliases to clarify the usage of `HashMap`s for storing global functions
and their analyzed versions. This change also refactors the
`LambdaCollector` and `Optimizer` to use these new aliases, improving
code readability and maintainability.

src/ast/compiler/bound_nodes.rs

@@ -60,6 +60,9 @@ pub type BoundNode<T = ()> = Node<BoundKind<T>, T>;
 /// Type alias for a node that has been fully type-checked.
 pub type TypedNode = BoundNode<StaticType>;
 
+/// Type alias for the global function registry.
+pub type GlobalFunctionRegistry = std::collections::HashMap<GlobalIdx, Rc<BoundNode>>;
+
 /// Metrics collected during the analysis phase.
 #[derive(Debug, Clone, PartialEq)]
 pub struct NodeMetrics {
@@ -71,6 +74,9 @@ pub struct NodeMetrics {
 /// Type alias for a node that has been analyzed.
 pub type AnalyzedNode = BoundNode<NodeMetrics>;
 
+/// Type alias for the global analyzed function registry.
+pub type GlobalAnalyzedRegistry = std::collections::HashMap<GlobalIdx, Rc<AnalyzedNode>>;
+
 #[derive(Debug, Clone)]
 pub enum BoundKind<T = ()> {
     Nop,