fix(joinir): Phase 283 P0 - Pattern3 Undefined ValueId Bug Fix

- Fix: extract_if_condition() moved after local_cond_env construction
  (loop_with_if_phi_if_sum.rs:175)
  - Root cause: condition extraction before i_param/sum_param creation
  - Result: i % 2 referenced caller's ConditionEnv with unmapped ValueId
- Fail-Fast: Add condition_bindings validation in merge (mod.rs)
- Fixture: Update loop_if_phi.hako for C2 compatibility (sum.toString())
- Verified: VM execution outputs sum=9 ✅

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

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

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

@@ -2,16 +2,15 @@
 
 ## Current Focus (next)
 
-- Phase 281（design-first）: `docs/development/current/main/phases/phase-281/README.md`
-  - P1 planned: Pattern6（early-exit）を compose に寄せる（挙動不変で段階移行）
-  - SSOT: `docs/development/current/main/design/edgecfg-fragments.md`, `src/mir/builder/control_flow/edgecfg/api/compose.rs`
-- Phase 282（planned, design-first）: Router shrinkage
-  - pattern番号を “症状ラベル（テスト名）” に降格し、合成SSOTへ寄せた後に router を縮退させる
+- Phase 283（bugfix）: JoinIR if-condition remap fix: `docs/development/current/main/phases/phase-283/README.md`
+  - 目的: Pattern3（if-sum）で `i % 2 == 1` が undefined `ValueId` を生成する不具合を根治する
+  - SSOT: `src/mir/join_ir/lowering/loop_with_if_phi_if_sum.rs`（ConditionEnv の正しい使用位置）
 
 ## Recently Completed (2025-12-23)
 
+- Phase 282（Router shrinkage + extraction-based migration P0–P5）: `docs/development/current/main/phases/phase-282/README.md`
 - Phase 280（Frag composition SSOT positioning）: `docs/development/current/main/phases/phase-280/README.md`
-- Phase 281 P0（Pattern7 → compose::if_）: `docs/development/current/main/phases/phase-281/README.md`
+- Phase 281（Pattern6/7 compose adoption, P0–P3）: `docs/development/current/main/phases/phase-281/README.md`
 - Phase 273（Plan line SSOT）: `docs/development/current/main/phases/phase-273/README.md`
 - Phase 275 P0（A1/B2/C2 coercion SSOT）: `docs/development/current/main/phases/phase-275/README.md`
 - Phase 276 P0（quick wins / type_helper SSOT）: `docs/development/current/main/phases/phase-276/README.md`