Initial commit: WAFER (WebAssembly Forth Engine in Rust)

Optimizing Forth 2012 compiler targeting WebAssembly with IR-based
compilation pipeline, multi-typed stack inference, subroutine threading,
and JIT/consolidation modes. Rust kernel with ~35 primitives and Forth
standard library for core/core-ext word sets.

crates/core/src/optimizer.rs

@@ -0,0 +1,19 @@
+//! Optimization passes for WAFER's IR.
+//!
+//! Each pass is a function `Vec<IrOp> -> Vec<IrOp>`, composable in sequence:
+//! 1. Constant folding
+//! 2. Strength reduction
+//! 3. Peephole optimization
+//! 4. Inlining
+//! 5. Dead code elimination
+//! 6. Stack-to-local promotion
+
+// TODO: Step 11 - Optimization pass implementations
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn placeholder() {
+        // Optimizer tests will be added in Step 11
+    }
+}