feat(llvm-py): Major breakthrough in Python LLVM backend! 🎉

✅ Print and FileBox paths now working correctly
✅ Resolver simplified by removing overly aggressive fast-path optimization
✅ Both OFF/ON in compare_harness_on_off.sh now use Python version
✅ String handle propagation issues resolved

Key changes:
- Removed instruction reordering in llvm_builder.py (respecting MIR order)
- Resolver now more conservative but reliable
- compare_harness_on_off.sh updated to use Python backend for both paths

This marks a major milestone towards Phase 15 self-hosting with Python/llvmlite!

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/backend/llvm_legacy/compiler/mock.rs

@@ -0,0 +1,23 @@
+use crate::mir::function::MirModule;
+use crate::box_trait::{NyashBox, IntegerBox};
+use std::collections::HashMap;
+
+pub struct LLVMCompiler {
+    values: HashMap<crate::mir::ValueId, Box<dyn NyashBox>>,
+}
+
+impl LLVMCompiler {
+    pub fn new() -> Result<Self, String> {
+        Ok(Self { values: HashMap::new() })
+    }
+
+    pub fn compile_module(&self, _mir: &MirModule, _out: &str) -> Result<(), String> {
+        // Mock: pretend emitted
+        Ok(())
+    }
+
+    pub fn compile_and_execute(&mut self, _mir: &MirModule, _out: &str) -> Result<Box<dyn NyashBox>, String> {
+        Ok(Box::new(IntegerBox::new(0)))
+    }
+}
+