feat(phase33): mir_call.hako Stages 2-4 complete - 全段階実装完了 🎉

Stage 2: CallEmitBox拡張 (+12 lines)
- make_mir_call_closure(params, captures, me_capture, dst)
- make_mir_call_value(func_vid, arg_ids, dst)

Stage 3: mir_call.hako簡略化 (208→164 lines, -21.2%)
- CallEmitBox完全活用により手動JSON生成を削除
- 74.4%削減達成 (Python 641→Hakorune 164 lines)

Stage 4: Smoke Tests追加 (+102 lines)
- closure_simple.hako: Closure callee typeテスト
- value_simple.hako: Value callee typeテスト

Phase 33 Final Achievement:
✅ 10/10 instructions 完全実装 (100%)
  - Phase v0: const, binop, compare, ret (4/4)
  - Phase v1: branch, jump, copy (3/3)
  - Phase v2-A: phi (1/1)
  - Phase v2-B: loopform (1/1)
  - Phase v2-C: mir_call (1/1) ← NEW!

Test Coverage:
- Unit tests: 288 lines (6 tests, all callee types)
- Smoke tests: 147 lines (3 tests)
- Total: 435 lines test coverage

🚀 Python → Hakorune Script 移行 100% 完了！

lang/src/compiler/emit/common/call_emit_box.hako

@@ -41,6 +41,19 @@ static box CallEmitBox {
     return {op: "mir_call", dst: dst, callee: callee, args: arg_ids}
   }
 
+  make_mir_call_closure(params, captures, me_capture, dst) {
+    local callee = {type: "Closure", params: params, captures: captures}
+    if me_capture != null {
+      callee.me_capture = me_capture
+    }
+    return {op: "mir_call", dst: dst, callee: callee, args: []}
+  }
+
+  make_mir_call_value(func_vid, arg_ids, dst) {
+    local callee = {type: "Value", value: func_vid}
+    return {op: "mir_call", dst: dst, callee: callee, args: arg_ids}
+  }
+
   _canonical_module_name(name, arity) {
     if name == null { return "" }
     if name.indexOf("/") >= 0 { return name }

lang/src/llvm_ir/instructions/mir_call.hako

@@ -114,71 +114,33 @@ static box LLVMMirCallInstructionBox {
   }
 
   // Stage 4: Closure creation
-  // TODO: CallEmitBox に make_mir_call_closure を追加する必要あり
+  // CallEmitBox.make_mir_call_closure を活用
   _lower_closure(self, callee, args, dst) {
-    // Placeholder: 将来実装
     local params = callee.get("params")
     local captures = callee.get("captures")
+    local me_capture = callee.get("me_capture")
 
-    local json = "{"
-    json = json + "\"op\":\"mir_call\""
-    json = json + ",\"dst\":" + dst.toString()
-    json = json + ",\"callee\":{\"type\":\"Closure\""
-
-    // params 配列
-    if params != null {
-      json = json + ",\"params\":" + me._array_to_json(self, params)
+    if params == null {
+      params = new ArrayBox()
+    }
+    if captures == null {
+      captures = new ArrayBox()
     }
 
-    // captures 配列
-    if captures != null {
-      json = json + ",\"captures\":" + me._array_to_json(self, captures)
-    }
-
-    json = json + "}"
-    json = json + ",\"args\":" + me._array_to_json(self, args)
-    json = json + "}"
-
-    return json
+    local json_obj = CallEmitBox.make_mir_call_closure(params, captures, me_capture, dst)
+    return JsonEmitBox.to_json_instruction(json_obj)
   }
 
   // Stage 4: Value call (dynamic function value)
-  // TODO: CallEmitBox に make_mir_call_value を追加する必要あり
+  // CallEmitBox.make_mir_call_value を活用
   _lower_value(self, callee, args, dst) {
-    // Placeholder: 将来実装
     local func_vid = callee.get("value")
     if func_vid == null {
       return me._mir_call_error_fallback(self, "Value: value is null")
     }
 
-    local json = "{"
-    json = json + "\"op\":\"mir_call\""
-    json = json + ",\"dst\":" + dst.toString()
-    json = json + ",\"callee\":{\"type\":\"Value\",\"value\":" + func_vid.toString() + "}"
-    json = json + ",\"args\":" + me._array_to_json(self, args)
-    json = json + "}"
-
-    return json
-  }
-
-  // Helper: ArrayBox を JSON 配列に変換
-  _array_to_json(self, arr) {
-    if arr == null {
-      return "[]"
-    }
-    local json = "["
-    local size = arr.size()
-    local i = 0
-    loop(i < size) {
-      if i > 0 {
-        json = json + ","
-      }
-      local val = arr.get(i)
-      json = json + val.toString()
-      i = i + 1
-    }
-    json = json + "]"
-    return json
+    local json_obj = CallEmitBox.make_mir_call_value(func_vid, args, dst)
+    return JsonEmitBox.to_json_instruction(json_obj)
   }
 
   // エラーフォールバック: 空の MIR Call を返す