🚀 Phase 10.11: Everything is Plugin革命完了！

主な変更:
- ConsoleBox/MathBoxプラグイン実装・登録完了
- nyash_box.toml 2ファイルシステム設計（中央レジストリ+個別仕様書）
- 全プラグインにnyash_box.tomlテンプレート追加
- プラグイン優先機能（NYASH_USE_PLUGIN_BUILTINS=1）文書化
- ビルトインBox削除準備（ChatGPT5実装中）
- ネイティブビルドデモ追加（Linux/Windows動作確認済み）

Everything is Box → Everything is Plugin への歴史的転換！
開発20日目にしてビルトインBox全削除という革命的決定。

🤖 Generated with Claude Code

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

docs/development/current/CURRENT_TASK.md

@@ -397,3 +397,16 @@ bash tools/build_aot.sh examples/aot_min_string_len.nyash -o app
 - 状態確認: `git status` / `git log --oneline -3` / `cargo check`
 - スモーク: `bash tools/smoke_phase_10_10.sh`
 - 次の一手: core_hostcall → core_ops の順に分割、毎回ビルド/スモークで確認
+
+---
+
+### 新規フェーズ（提案）: Phase 10.11 Builtins → Plugins 移行
+- 目的: 内蔵Box経路を段階的に廃止し、プラグイン/ユーザーBoxに一本化する（不具合の温床を解消）
+- 現在の足場（済）:
+  - ConsoleBox コンストラクタをレジストリ委譲（プラグイン優先）に変更
+  - `NYASH_DISABLE_BUILTINS=1` でビルトインFactory登録を抑止可能
+  - 設計ドキュメント: docs/development/roadmap/phases/phase-10.11-builtins-to-plugins.md
+- 次ステップ:
+  - 非基本コンストラクタの委譲徹底（Math/Random/Sound/Debugなど）
+  - 主要ビルトインの plugin 化（nyash_box.toml 整備）
+  - CIに `NYASH_USE_PLUGIN_BUILTINS=1` / `NYASH_PLUGIN_OVERRIDE_TYPES` のスモークを追加

docs/development/roadmap/phases/phase-10.11-builtins-to-plugins.md

@@ -0,0 +1,54 @@
+# Phase 10.11: Builtins → Plugins Migration
+
+## Goals
+- Remove builtin Box implementations from execution paths (Interpreter/VM/JIT) to avoid divergence and double sources of truth.
+- Provide all functionality via plugins (BID-FFI v1) and/or user-defined boxes.
+- Keep backward compatibility guarded behind env flags until migration completes.
+
+## Rationale
+- Conflicts like ConsoleBox builtin vs plugin cause unexpected behavior.
+- Native build (AOT/EXE) path benefits from uniform plugin boundary.
+- One registry, one implementation per Box: simpler, safer.
+
+## Plan (Incremental)
+1) Disable Switch (Now)
+- Add `NYASH_DISABLE_BUILTINS=1` to skip registering builtin box factory.
+- Keep off by default; use in CI lanes and targeted tests.
+
+2) Constructor Delegation (Now → Next)
+- Ensure all constructors go through the unified registry, not direct builtin instantiation.
+- Done: ConsoleBox; Next: remaining non-basic constructors.
+
+3) Override Policy (Ongoing)
+- Use `NYASH_USE_PLUGIN_BUILTINS=1` + `NYASH_PLUGIN_OVERRIDE_TYPES` to prefer plugins for selected types.
+- Grow the allowlist as plugins become available.
+
+4) Plugin Coverage (Milestones)
+- ConsoleBox (stdout) — done
+- Array/Map/String/Integer — in place
+- File/Net/Python — in place
+- Math/Time/etc. — add `nyash_box.toml` and minimal plugins
+
+5) Remove Builtins (Final)
+- Remove builtin factory or move into separate optional crate for legacy runs.
+- Update docs, examples, and CI to plugin-only.
+
+## Acceptance Criteria
+- `NYASH_DISABLE_BUILTINS=1` + plugin set → examples run green (VM path).
+- No direct builtins in interpreter constructors (registry only).
+- JIT/AOT compile from MIR uses only plugin invoke shims for Box methods.
+
+## How to Test
+```bash
+# Strict plugin preference + disable builtins
+export NYASH_USE_PLUGIN_BUILTINS=1
+export NYASH_PLUGIN_OVERRIDE_TYPES="ArrayBox,MapBox,ConsoleBox,StringBox,IntegerBox"
+export NYASH_DISABLE_BUILTINS=1
+
+cargo build --release --features cranelift-jit
+./target/release/nyash --backend vm examples/console_demo.nyash
+```
+
+## Notes
+- Temporary breakages expected when some builtin-only boxes remain. Use the override allowlist tactically.
+- Keep `[libraries]` and `[plugins]` configured to ensure provider discovery.