📚 Phase 11 documentation: Everything is Box × MIR15 revolution

Key updates:
- Document MIR 26→15 instruction reduction plan (transitioning status)
- Add Core-15 target instruction set in INSTRUCTION_SET.md
- Save AI conference analyses validating Box Theory and 15-instruction design
- Create MIR annotation system proposal for optimization hints
- Update SKIP_PHASE_10_DECISION.md with LLVM direct migration rationale

Technical insights:
- RefNew/RefGet/RefSet can be eliminated through Box unification
- GC/sync/async all achievable with 15 core instructions
- BoxCall lowering can automatically insert GC barriers
- 2-3x performance improvement expected with LLVM
- Build time reduction 50%, binary size reduction 40%

Status: Design complete, implementation pending

src/runner/modes/vm.rs

@@ -55,9 +55,18 @@ impl NyashRunner {
             }
         }
 
+        // Optional: VM-only escape analysis to elide barriers before execution
+        let mut module_vm = compile_result.module.clone();
+        if std::env::var("NYASH_VM_ESCAPE_ANALYSIS").ok().as_deref() == Some("1") {
+            let removed = nyash_rust::mir::passes::escape::escape_elide_barriers_vm(&mut module_vm);
+            if removed > 0 && std::env::var("NYASH_CLI_VERBOSE").ok().as_deref() == Some("1") {
+                eprintln!("[VM] escape_elide_barriers: removed {} barriers", removed);
+            }
+        }
+
         // Execute with VM using prepared runtime
         let mut vm = VM::with_runtime(runtime);
-        match vm.execute_module(&compile_result.module) {
+        match vm.execute_module(&module_vm) {
             Ok(result) => {
                 println!("✅ VM execution completed successfully!");
                 // Pretty-print using MIR return type when available to avoid Void-looking floats/bools