Refactor: Remove explicit upvalue analysis pass

The `UpvalueAnalyzer` pass is no longer necessary as the binder now
directly tracks captures. This commit removes the `UpvalueAnalyzer`
struct and associated logic from `src/ast/compiler/upvalues.rs`.

The `Binder::bind_root` function now returns the `captures` map, which
is then processed by a new `CapturePass` in `src/ast/environment.rs`
before type checking. This consolidates capture logic within the binder
and its subsequent processing steps.

src/ast/compiler/macros.rs

@@ -713,7 +713,15 @@ mod tests {
         let expanded = expander.expand(untyped).unwrap();
 
         let mut global_names = HashMap::new();
-        global_names.insert(Symbol::from("*"), 0);
+        global_names.insert(
+            Symbol::from("*"),
+            (
+                0,
+                Rc::new(crate::ast::types::NodeIdentity {
+                    location: crate::ast::types::SourceLocation { line: 0, col: 0 },
+                }),
+            ),
+        );
         let globals = Rc::new(RefCell::new(global_names));
 
         let result = Binder::bind_root(globals, &expanded);
@@ -740,8 +748,8 @@ mod tests {
         let expanded = expander.expand(untyped).unwrap();
 
         let globals = Rc::new(RefCell::new(HashMap::new()));
-        let bound = Binder::bind_root(globals, &expanded);
-        assert!(bound.is_ok(), "Hygiene failed: {:?}", bound.err());
+        let result = Binder::bind_root(globals, &expanded);
+        assert!(result.is_ok(), "Hygiene failed: {:?}", result.err());
     }
 
     #[test]
@@ -760,11 +768,11 @@ mod tests {
         let expanded = expander.expand(untyped).unwrap();
 
         let globals = Rc::new(RefCell::new(HashMap::new()));
-        let bound = Binder::bind_root(globals, &expanded);
+        let result = Binder::bind_root(globals, &expanded);
         assert!(
-            bound.is_ok(),
+            result.is_ok(),
             "Explicit Hygiene with Backticks failed: {:?}",
-            bound.err()
+            result.err()
         );
     }
 }