docs: note Phase 110-112 control_tree status

- Update 10-Now.md with Phase 112 completion
- Note: StepTree capability guard (strict-only) implemented
- Note: Default behavior unchanged, only affects HAKO_JOINIR_STRICT=1

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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

@@ -1,5 +1,39 @@
 # Self Current Task — Now (main)
 
+## 2025-12-18：Phase 112 完了 ✅
+
+**Phase 112: StepTree Capability Guard (strict-only)**
+- StepTree の required_caps を strict mode でチェック
+- Allowlist: If, NestedIf, Loop, Return, Break, Continue
+- Deny (strict): NestedLoop, TryCatch, Throw, Lambda, While, ForRange, Match, Arrow
+- Error format: `[joinir/control_tree/cap_missing/<Cap>] <msg>  Hint: <hint>`
+- Default behavior unchanged (strict=false always Ok)
+- 入口: `docs/development/current/main/design/control-tree.md`
+- 実装:
+  - `src/mir/builder/control_flow/joinir/control_tree_capability_guard.rs`
+  - `src/mir/builder/calls/lowering.rs` (wired into lower_function_body)
+
+## 2025-12-18：Phase 111 完了 ✅
+
+**Phase 111: StepTreeContract + StepTreeSignature（dev-only）**
+- StepTreeContract を追加（`exits` / `writes` / `required_caps` / `cond_sig`）
+- StepTreeSignature を追加（`signature_basis_string()` を安定 hash、Span は含めない）
+- dev-only parity を break/continue に加えて return まで拡張
+- 入口: `docs/development/current/main/design/control-tree.md`
+- 実装: `src/mir/control_tree/step_tree.rs`
+
+## 2025-12-18：Phase 110 完了 ✅
+
+**Phase 110: ControlTree / StepTree（構造SSOT・dev-only観測）**
+- StepTree の語彙（Block/If/Loop/Stmt）と Feature を pure AST で実装（ValueId/PHI/CFG を混ぜない）
+- joinir routing 側で extractor との “分類矛盾” を dev-only で検出（strict のみ Fail-Fast）
+- 関数本体の StepTree を dev-only でダンプ（既定挙動不変）
+- 入口: `docs/development/current/main/design/control-tree.md`
+- 実装:
+  - `src/mir/control_tree/step_tree.rs`
+  - `src/mir/builder/calls/lowering.rs`
+  - `src/mir/builder/control_flow/joinir/routing.rs`
+
 ## 2025-12-17：Phase 109 完了 ✅
 
 **Phase 109: error_tags hints SSOT**