🎉 Phase 11.8/12.7: MIR Core-13 完全実装 + 糖衣構文ドキュメント更新

主要な変更:
- MIR Core-13命令セット確定（Load/Store削除の革命的設計）
  - Const, BinOp, Compare（値・計算）
  - Jump, Branch, Return, Phi（制御）
  - Call, BoxCall, ExternCall（呼び出し）
  - TypeOp, Safepoint, Barrier（メタ）
- Phase 12.7糖衣構文ドキュメント整理（超圧縮重視、可逆変換保証）
- MIRビルダーのモジュール分割完了
- vtableテストスイート拡充
- AI協調開発ツール追加（並列リファクタリング支援）

詳細:
- src/mir/instruction_introspection.rs: core13_instruction_names()追加
- MIRビルダー分割: decls.rs, exprs_*.rs, fields.rs
- plugin_loader_v2: errors.rs, host_bridge.rs分離
- 論文用データ: mir13-final.md作成

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

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

src/mir/builder/utils.rs

@@ -1,4 +1,5 @@
 use std::fs;
+use super::{BasicBlock, BasicBlockId};
 
 // Resolve include path using nyash.toml include.roots if present
 pub(super) fn resolve_include_path_builder(filename: &str) -> String {
@@ -63,3 +64,29 @@ pub(super) fn infer_type_from_phi(
     None
 }
 
+// Lightweight helpers moved from builder.rs to reduce file size
+impl super::MirBuilder {
+    /// Ensure a basic block exists in the current function
+    pub(crate) fn ensure_block_exists(&mut self, block_id: BasicBlockId) -> Result<(), String> {
+        if let Some(ref mut function) = self.current_function {
+            if !function.blocks.contains_key(&block_id) {
+                let block = BasicBlock::new(block_id);
+                function.add_block(block);
+            }
+            Ok(())
+        } else {
+            Err("No current function".to_string())
+        }
+    }
+
+    /// Start a new basic block and set as current
+    pub(crate) fn start_new_block(&mut self, block_id: BasicBlockId) -> Result<(), String> {
+        if let Some(ref mut function) = self.current_function {
+            function.add_block(BasicBlock::new(block_id));
+            self.current_block = Some(block_id);
+            Ok(())
+        } else {
+            Err("No current function".to_string())
+        }
+    }
+}