feat: Specialize pipeline types for performance

Introduces type specialization for reactive pipeline nodes and their
data buffers. This eliminates the overhead of generic `Value` enums and
`SharedValueSeries` when dealing with known scalar or record types.

The architecture shifts buffer instantiation from the VM to the runtime
(RTL), leveraging type information from the AST. A new `out_type` field
is added to `BoundKind::Pipe` to store the static type of the pipeline's
output, determined by the type checker.

This enables the creation of specialized `RingBuffer<T>` and
`SharedRecordSeries` (for Struct-of-Arrays layout) when the output type
is known, significantly improving memory usage and processing speed for
time-series data, especially in financial analysis.

src/ast/compiler/optimizer/engine.rs

@@ -386,7 +386,7 @@ impl Optimizer {
                 )
             }
 
-            BoundKind::Pipe { inputs, lambda } => {
+            BoundKind::Pipe { inputs, lambda, out_type } => {
                 let mut o_inputs = Vec::with_capacity(inputs.len());
                 for input in inputs {
                     o_inputs.push(self.visit_node(input, sub, path));
@@ -396,6 +396,7 @@ impl Optimizer {
                     BoundKind::Pipe {
                         inputs: o_inputs,
                         lambda: o_lambda,
+                        out_type: out_type.clone(),
                     },
                     node.ty.clone(),
                 )