fix(joinir): Correct JsonShapeToMap function name and add Phase 33-5 test whitelist

Changes:
1. **Naming fix**: JsonShapeParser → JsonShapeToMap
   - Updated function name in whitelist to match actual static box name
   - Affected: JsonShapeToMap._read_value_from_pair/1 (lang/src/runtime/meta/json_shape_parser.hako)

2. **Phase 33-5 test whitelist**: Added Stage1JsonScannerTestBox.* pattern
   - Enables A/B testing for Stage-B if/else patterns
   - Test verified: Route A (if_phi) and Route B (Select) both RC=0 ✅

Testing:
- Route A (NYASH_JOINIR_IF_SELECT=0): RC 0 ✓
- Route B (NYASH_JOINIR_IF_SELECT=1): RC 0 ✓
- Pattern: simple if/else return (Stage1JsonScannerBox.value_start_after_key_pos/2 style)

Phase 33-5: Stage-B if/Select A/B testing実施完了

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

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

src/mir/join_ir/lowering/mod.rs

@@ -51,7 +51,7 @@ use crate::mir::{BasicBlockId, MirFunction};
 /// Scope:
 /// - Only applies to whitelisted functions:
 ///   - IfSelectTest.* (Phase 33-2/33-3)
-///   - JsonShapeParser._read_value_from_pair/1 (Phase 33-4 Stage-1)
+///   - JsonShapeToMap._read_value_from_pair/1 (Phase 33-4 Stage-1)
 ///   - Stage1JsonScannerBox.value_start_after_key_pos/2 (Phase 33-4 Stage-B)
 /// - Requires NYASH_JOINIR_IF_SELECT=1 environment variable
 /// - Falls back to traditional if_phi on pattern mismatch
@@ -67,9 +67,10 @@ pub fn try_lower_if_to_joinir(
         return None;
     }
 
-    // Phase 33-4: 関数名ガード拡張（IfSelectTest + Stage-1/Stage-B 候補）
+    // Phase 33-4/33-5: 関数名ガード拡張（テスト + Stage-1/Stage-B 候補）
     let is_allowed = func.signature.name.starts_with("IfSelectTest.")
-        || func.signature.name == "JsonShapeParser._read_value_from_pair/1"
+        || func.signature.name.starts_with("Stage1JsonScannerTestBox.") // Phase 33-5 test
+        || func.signature.name == "JsonShapeToMap._read_value_from_pair/1"
         || func.signature.name == "Stage1JsonScannerBox.value_start_after_key_pos/2";
 
     if !is_allowed {