Perf: Restore core optimizations and stabilize VM execution

This commit restores and enhances several high-performance features that
were
previously lost, while fixing critical bugs in scope management.

Performance Optimizations:
- Zero-Copy TCO: Refactored TailCallRequest to use (Rc, usize), moving
  arguments
  directly on the VM stack via drain/resize instead of heap-allocating
  Vecs.
- Slice-based Calls: Native functions and field accessors now operate
  directly
  on stack slices, significantly reducing memory churn.
- SoA Push Fast-Path: Restored specialized 'push' intrinsic for
  RecordSeries.
  Matches layouts via Arc::ptr_eq to distribute values directly into
  columns
  without keyword lookups.

Architectural Improvements:
- Static Stack Frames (max_slots): The Binder now calculates the maximum

  required slots per lambda. The VM pre-resizes the stack frame,
  preventing
  collisions between local variables and temporary call arguments.
- Macro Hygiene: Fixed a bug where macro-internal variables could
  overwrite
  outer call arguments due to stack overlap.
- Trait Refactoring: Unified series operations via a polymorphic
  'push_value'
  on the Series trait, with a generic implementation for
  ScalarSeries<T>.

Code Quality:
- Resolved all 'cargo clippy' warnings (collapsible ifs, redundant
  borrows, etc).
- Restored 100% test pass rate (64/64 tests).
- Verified stability of all examples and benchmarks.

src/ast/types.rs

@@ -202,6 +202,9 @@ pub trait Series {
     /// Gets the value at the specified lookback index (0 = newest).
     fn get_item(&self, index: usize) -> Option<Value>;
 
+    /// Pushes a new value into the series.
+    fn push_value(&self, value: Value);
+
     /// Returns the current number of elements in the buffer.
     fn len(&self) -> usize;
 
@@ -259,7 +262,7 @@ pub enum Value {
     Function(Rc<NativeFunction>),
     Object(Rc<dyn Object>),   // For compiled Closures and other opaque types
     Cell(Rc<RefCell<Value>>), // Boxed value for captures
-    TailCallRequest(Box<(Rc<dyn Object>, Vec<Value>)>), // Internal: For TCO (Boxed to keep Value small)
+    TailCallRequest(Rc<dyn Object>, usize), // Internal: For TCO (target object + argc on stack)
 }
 
 impl PartialEq for Value {
@@ -280,8 +283,8 @@ impl PartialEq for Value {
             (Value::Function(a), Value::Function(b)) => Rc::ptr_eq(a, b),
             (Value::Object(a), Value::Object(b)) => Rc::ptr_eq(a, b),
             (Value::Cell(a), Value::Cell(b)) => Rc::ptr_eq(a, b),
-            (Value::TailCallRequest(a), Value::TailCallRequest(b)) => {
-                Rc::ptr_eq(&a.0, &b.0) && a.1 == b.1
+            (Value::TailCallRequest(oa, ca), Value::TailCallRequest(ob, cb)) => {
+                Rc::ptr_eq(oa, ob) && ca == cb
             }
             _ => false,
         }
@@ -527,11 +530,12 @@ impl StaticType {
 }
 
 impl Value {
-    pub fn as_float(&self) -> Option<f64> {
+    pub fn get_field(&self, key: Keyword) -> Option<Value> {
         match self {
-            Value::Float(f) => Some(*f),
-            Value::Int(i) => Some(*i as f64),
-            _ => None,
+            Value::Record(layout, values) => {
+                layout.index_of(key).map(|idx| values[idx].clone())
+            }
+            _ => None
         }
     }
 
@@ -544,6 +548,14 @@ impl Value {
         }
     }
 
+    pub fn as_float(&self) -> Option<f64> {
+        match self {
+            Value::Float(f) => Some(*f),
+            Value::Int(i) => Some(*i as f64),
+            _ => None,
+        }
+    }
+
     pub fn is_truthy(&self) -> bool {
         match self {
             Value::Void => false,
@@ -623,7 +635,7 @@ impl Value {
             Value::Function(_) => StaticType::Any, // Dynamic function
             Value::Object(o) => StaticType::Object(o.type_name()),
             Value::Cell(c) => c.borrow().static_type(),
-            Value::TailCallRequest(_) => StaticType::Any, // Internal state, but typable as Any
+            Value::TailCallRequest(_, _) => StaticType::Any, // Internal state, but typable as Any
         }
     }
 }
@@ -680,7 +692,7 @@ impl fmt::Display for Value {
                 }
             }
             Value::Cell(c) => write!(f, "{}", c.borrow()),
-            Value::TailCallRequest(_) => write!(f, "<tail call request>"),
+            Value::TailCallRequest(_, _) => write!(f, "<tail call request>"),
         }
     }
 }