phase29ap(p2): route stdlib to_lower via plan char-map subset

docs/development/current/main/10-Now.md

@@ -3,7 +3,7 @@
 ## Current Focus
 
 - Phase: `docs/development/current/main/phases/phase-29ap/README.md`
-- Next: Phase 29ap P2 (planned; see `docs/development/current/main/phases/phase-29ap/README.md`)
+- Next: Phase 29ap P3 (planned; see `docs/development/current/main/phases/phase-29ap/README.md`)
 
 ## Gate (SSOT)
 

docs/development/current/main/30-Backlog.md

@@ -5,7 +5,7 @@ Scope: 「次にやる候補」を短く列挙するメモ。入口は `docs/dev
 
 ## Active
 
-- Phase 29ap: `docs/development/current/main/phases/phase-29ap/README.md` (Next: P2 planned)
+- Phase 29ap: `docs/development/current/main/phases/phase-29ap/README.md` (Next: P3 planned)
 - JoinIR regression gate SSOT: `docs/development/current/main/phases/phase-29ae/README.md`
 - CorePlan hardening (docs-first): `docs/development/current/main/phases/phase-29al/README.md`
 

docs/development/current/main/design/coreplan-migration-roadmap-ssot.md

@@ -34,7 +34,7 @@ Related:
 ## 1.1 Current (active)
 
 - Active phase: `docs/development/current/main/phases/phase-29ap/README.md`
-- Next step: Phase 29ap P1 (planned)
+- Next step: Phase 29ap P3 (planned)
 
 ## 2. すでに固めた SSOT（再発防止の土台）
 

docs/development/current/main/phases/phase-29ae/README.md

@@ -12,6 +12,7 @@ Goal: JoinIR の最小回帰セットを SSOT として固定する。
 - Pattern3 (release adopt, VM): `phase29ao_pattern3_release_adopt_vm`
 - Pattern1 (strict shadow, VM): `phase29ao_pattern1_strict_shadow_vm`
 - Pattern1 (subset reject, VM): `phase29ao_pattern1_subset_reject_extra_stmt_vm`
+- Pattern1 (stdlib to_lower, VM): `phase29ap_stringutils_tolower_vm`
 - Pattern5 (Break, VM): `phase286_pattern5_break_vm`
 - Pattern5 (strict shadow, VM): `phase29ao_pattern5_strict_shadow_vm`
 - Pattern5 (release adopt, VM): `phase29ao_pattern5_release_adopt_vm`

docs/development/current/main/phases/phase-29ap/P2-PATTERN1-STDLIB-TO_LOWER-SUBSET-INSTRUCTIONS.md

@@ -0,0 +1,70 @@
+---
+Status: Ready
+Scope: code+tests+docs (Pattern1 stdlib to_lower subset via Plan SSOT)
+Related:
+  - docs/development/current/main/phases/phase-29ap/README.md
+  - docs/development/current/main/design/coreplan-migration-roadmap-ssot.md
+  - docs/development/current/main/phases/phase-29ae/README.md
+  - tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh
+  - apps/lib/json_native/utils/string.hako
+  - src/mir/builder/control_flow/plan/facts/pattern1_char_map_facts.rs
+  - src/mir/builder/control_flow/plan/normalizer/pattern1_char_map.rs
+  - src/mir/builder/control_flow/joinir/patterns/router.rs
+---
+
+# Phase 29ap P2: Pattern1 stdlib to_lower subset via Plan SSOT
+
+Date: 2025-12-30  
+Status: Ready for execution  
+Goal: StringUtils.to_lower の loop を Plan/Facts/Normalizer で受理し、JoinIR Pattern1 依存を撤去する（既定挙動は不変）。
+
+## 非目的
+
+- Pattern1 の一般拡張（任意の body を許す）
+- 新しい env var / 恒常ログ追加
+- 既存の release/strict 挙動やエラー文字列の変更
+
+## 実装方針（SSOT）
+
+### 1) Facts: stdlib to_lower 形状を SSOT 化
+
+- 新規: `pattern1_char_map_facts.rs`
+  - 形状（超保守）:
+    - condition: `i < s.length()` のみ
+    - body: `local ch = s.substring(i, i+1)` / `result = result + this.method(ch)` / `i = i + 1`
+    - break/continue/return/if は不可
+  - 失敗は `Ok(None)`（fallback 維持）
+
+### 2) Planner: DomainPlan を追加
+
+- 新規: `DomainPlan::Pattern1CharMap`
+- Facts から 1 候補だけ生成（ambiguous は Freeze）
+
+### 3) Normalizer: CorePlan へ拡張
+
+- 新規: `normalize_pattern1_char_map`
+  - 2 PHI（loop var + result）
+  - substring → transform method → result add を step block で構成
+  - static box の `this.method()` は `current_static_box` から const 受け口で処理
+
+### 4) Smoke: to_lower を gate に入れる
+
+- 新規 fixture: `apps/tests/phase29ap_stringutils_tolower_min.hako`
+- 新規 smoke: `tools/smokes/v2/profiles/integration/joinir/phase29ap_stringutils_tolower_vm.sh`
+- gate へ追加: `phase29ae_regression_pack_vm.sh`
+- docs: `phase-29ae/README.md` に追記
+
+### 5) JoinIR router の Pattern1 は保留（stdlib join が依存）
+
+- `LOOP_PATTERNS` の Pattern1 は残す（StringUtils.join が plan で未対応なため）
+- to_lower は Plan 経路で通ることを smoke で確認
+
+## 検証（必須）
+
+- `cargo build --release`
+- `./tools/smokes/v2/run.sh --profile quick`
+- `./tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh`
+
+## コミット
+
+- `git commit -m "phase29ap(p2): route stdlib to_lower via plan char-map subset"`

docs/development/current/main/phases/phase-29ap/README.md

@@ -33,7 +33,17 @@ Gate (SSOT):
 - Guardrails:
   - No change to pattern selection or logs.
 
+## P2: Pattern1 stdlib to_lower subset (Plan SSOT) ✅
+
+- Scope:
+  - Add char-map Facts/Planner/Normalizer path for StringUtils.to_lower (subset).
+  - Add regression smoke for stdlib to_lower and wire it into JoinIR gate.
+  - Keep Pattern1 in JoinIR legacy router table for stdlib join until a plan-based subset exists.
+- Guardrails:
+  - No new logs or error strings.
+  - Fallback remains `Ok(None)` when shape does not match.
+
 ## Next (planned)
 
-- P2: Router pattern-name branching reduction (planner outcome + composer SSOT)
-- P3: Facts/Feature expansion if needed
+- P3: Router pattern-name branching reduction (planner outcome + composer SSOT)
+- P4: Facts/Feature expansion if needed