fix: step1 覆盖反馈重试从 1 次增加到最多 2 次 - Closes #54

首次重试修复完路径/格式问题后，如果覆盖率仍不达标，追加第二轮重试
以进一步补充缺失的功能单元，降低 QE Audit inadequate_ratio。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

skills/ir_generation_skill/step1_semantic_index.py

@@ -880,10 +880,14 @@ def run_ensemble_semantic_index(doc: dict) -> dict:
             if v:
                 print(f"    {k}: {len(v)} 个问题")
 
-        # Feedback retry: re-run with coverage feedback (one retry)
+        # Feedback retry: re-run with coverage feedback (up to 2 retries)
+        retry_count = 0
+        while retry_count < 2:
             feedback = _build_coverage_feedback(gaps)
-        if feedback:
-            print(f"\n  覆盖反馈重试 (feedback长度={len(feedback)}字符)...", flush=True)
+            if not feedback:
+                break
+            retry_count += 1
+            print(f"\n  覆盖反馈重试 #{retry_count} (feedback长度={len(feedback)}字符)...", flush=True)
             try:
                 retry_prompt = build_prompt(doc, feedback, all_paths)
                 print(f"  重试 prompt 长度: {len(retry_prompt)} 字符", flush=True)
@@ -892,17 +896,15 @@ def run_ensemble_semantic_index(doc: dict) -> dict:
                 n_retry_concepts = len(retry_result.get("concepts", []))
                 print(f"  重试返回: {n_retry_concepts} 概念, {n_retry_units} 功能单元", flush=True)
                 if n_retry_units > 0:
-                    # Check which new sections were covered
                     retry_sections = set()
                     for fu in retry_result.get("function_units", []):
                         for src in fu.get("sources", []):
                             if src.get("section"):
                                 retry_sections.add(src["section"])
                     print(f"  重试新增 sections: {sorted(retry_sections)}", flush=True)
-                    # Merge retry into results and re-validate
                     semantic_indices.append(retry_result)
                     merged = ensemble_merge(semantic_indices)
-                    merged["ensemble_temperatures"] = list(temperatures) + ["feedback_retry"]
+                    merged["ensemble_temperatures"] = list(temperatures) + [f"feedback_retry_{retry_count}"]
                     passed, gaps = _quick_validate(merged, doc, all_paths)
                     merged["validation_passed"] = passed
                     merged["validation_gaps"] = {
@@ -913,6 +915,7 @@ def run_ensemble_semantic_index(doc: dict) -> dict:
                 print(f"  覆盖反馈重试失败: {e}", flush=True)
                 import traceback
                 traceback.print_exc()
+                break
 
     return merged