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>

apps/tests/loop_if_phi.hako

@@ -7,8 +7,7 @@ static box Main {
       if (i % 2 == 1) { sum = sum + i } else { sum = sum + 0 }
       i = i + 1
     }
-    console.println("sum=" + sum)
+    console.println("sum=" + sum.toString())
     return 0
   }
 }
-