fix(mir): PHI検証panic修正 - update_cfg()を検証前に呼び出し

A案実装: debug_verify_phi_inputs呼び出し前にCFG predecessorを更新

修正箇所（7箇所）:
- src/mir/builder/phi.rs:50, 73, 132, 143
- src/mir/builder/ops.rs:273, 328, 351

根本原因:
- Branch/Jump命令でsuccessorは即座に更新
- predecessorはupdate_cfg()で遅延再構築
- PHI検証が先に実行されてpredecessor未更新でpanic

解決策:
- 各debug_verify_phi_inputs呼び出し前に
  if let Some(func) = self.current_function.as_mut() {
      func.update_cfg();
  }
  を挿入してCFGを同期

影響: if/else文、論理演算子(&&/||)のPHI生成が正常動作

lang/src/compiler/pipeline_v2/pipeline.hako

@@ -256,22 +256,31 @@ flow PipelineV2 {
     {
       local kq = RegexFlow.find_from(ast_json, "\"type\":\"Call\"", 0)
       if kq >= 0 {
+        print("[flow] Call pattern: kq=" + kq)
         // Strict preflight via tolerant scanner: read raw name and enforce using alias resolution
         {
           local scan0 = Stage1JsonScannerBox.extract_name_args(ast_json, kq)
           if scan0 != null {
-            if AliasPreflightBox.check_head(scan0.get("name"), r) != 1 { return null }
+            print("[flow] Call scan0 name=" + scan0.get("name"))
+            if AliasPreflightBox.check_head(scan0.get("name"), r) != 1 {
+              print("[flow] Call AliasPreflightBox failed, returning null")
+              return null
+            }
           }
         }
 
         local kc = CallExtractBox.extract_return_call_ints(ast_json)
         if kc != null {
+          print("[flow] Call extract_return_call_ints succeeded")
           local kn = NormalizerBox.normalize_call_ints(kc)
-          if kn == null { return null }
-          if SignatureVerifierBox.verify_call_name_arity(kn.get("name"), kn.get("args")) != 1 { return null }
+          if kn == null { print("[flow] Call normalize_call_ints returned null") return null }
+          if SignatureVerifierBox.verify_call_name_arity(kn.get("name"), kn.get("args")) != 1 { print("[flow] Call verify_call_name_arity failed") return null }
           local j4 = EmitCallBox.emit_call_int_args(kn.get("name"), kn.get("args"))
-          if j4 == null { return null }
+          if j4 == null { print("[flow] Call emit_call_int_args returned null") return null }
+          print("[flow] Call path 1 succeeded, returning JSON")
           return LocalSSA.ensure_calls(LocalSSA.ensure_cond(j4))
+        } else {
+          print("[flow] Call extract_return_call_ints returned null, trying scanner fallback")
         }
         // Fallback: scanner → normalizer → emit
         {