feat(joinir): Phase 248 - Normalized JoinIR infrastructure

Major refactoring of JoinIR normalization pipeline:

Key changes:
- Structured→Normalized→MIR(direct) pipeline established
- ShapeGuard enhanced with Pattern2 loop validation
- dev_env.rs: New development fixtures and env control
- fixtures.rs: jsonparser_parse_number_real fixture
- normalized_bridge/direct.rs: Direct MIR generation from Normalized
- pattern2_step_schedule.rs: Extracted step scheduling logic

Files changed:
- normalized.rs: Enhanced NormalizedJoinModule with DevEnv support
- shape_guard.rs: Pattern2-specific validation (+300 lines)
- normalized_bridge.rs: Unified bridge with direct path
- loop_with_break_minimal.rs: Integrated step scheduling
- Deleted: step_schedule.rs (moved to pattern2_step_schedule.rs)

New files:
- param_guess.rs: Loop parameter inference
- pattern2_step_schedule.rs: Step scheduling for Pattern2
- phase43-norm-canon-p2-mid.md: Design doc

Tests: 937/937 PASS (+6 from baseline 931)

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

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

docs/development/current/main/phase224-digitpos-condition-normalizer.md

@@ -1,5 +1,8 @@
 # Phase 224-E: DigitPos Condition Normalizer
 
+Status: Active（DigitPos 条件正規化ラインの設計メモ / 実装ガイド）  
+Scope: digit_pos → is_digit_pos Carrier / ConditionEnv / ExprLowerer の正規化経路の SSOT ドキュメントだよ。Phase 26‑H / 34 系の JsonParser `_parse_number` / `_atoi` でもこの設計を前提にしている。
+
 ## Problem Statement
 
 ### Background