fix: 修复 AI Code Review 阻塞问题

1. can_generate 自动修复中 assign_asset 加 try-except，避免单个失败导致整体崩溃
2. 移除 generation.py 冗余 DB 查询，诊断日志移入 can_generate 内部
3. 增加详细诊断日志：clips_with_asset 数量、config_asset_ids 数量

apps/api/app/api/routes/templates_editor/generation.py

@@ -74,22 +74,7 @@ def generate_editor_draft(
         plan_svc, plan_id, plan_check, clips_without_asset, asset_library_repo, asset_repo
     )
 
-    # ── 防御性诊断日志：fallback 链路结束后、can_generate 前 ──
-    _post_fallback_plan = plan_svc.get_plan_or_raise(plan_id)
-    _post_fallback_clips = plan_svc.list_clips(plan_id)
-    _post_fallback_asset_ids = (_post_fallback_plan.config or {}).get("asset_ids", [])
-    _post_fallback_clips_with_asset = sum(1 for c in _post_fallback_clips if c.asset_id)
-    logger.info(
-        "模板编辑器 fallback 链路完成: plan=%s status=%s "
-        "total_clips=%d clips_with_asset=%d config_asset_ids_count=%d",
-        plan_id,
-        _post_fallback_plan.status,
-        len(_post_fallback_clips),
-        _post_fallback_clips_with_asset,
-        len(_post_fallback_asset_ids),
-    )
-
-    # 检查是否可生成（含最后防线自动修复）
+    # 检查是否可生成（含最后防线自动修复 + 诊断日志）
     try:
         can_gen, reason = plan_svc.can_generate(plan_id)
     except ValueError as exc:

apps/api/app/services/edit_plan_service.py

@@ -591,6 +591,17 @@ class EditPlanService:
 
         # 检查是否至少有一个片段分配了素材
         has_asset = any(c.asset_id for c in clips)
+        config_asset_ids_count = len((plan.config or {}).get("asset_ids", []))
+        clips_with_asset_count = sum(1 for c in clips if c.asset_id)
+        logger.info(
+            "can_generate 诊断: plan=%s status=%s total_clips=%d "
+            "clips_with_asset=%d config_asset_ids_count=%d",
+            plan_id,
+            plan.status,
+            len(clips),
+            clips_with_asset_count,
+            config_asset_ids_count,
+        )
         if not has_asset:
             # ── 最后防线：自动从 config.asset_ids 分配素材 ──
             config_asset_ids = (plan.config or {}).get("asset_ids", [])
@@ -602,12 +613,24 @@ class EditPlanService:
                     len(config_asset_ids),
                 )
                 clips_without_asset = [c for c in clips if not c.asset_id]
+                assigned_count = 0
                 for i, clip in enumerate(clips_without_asset):
                     asset_idx = i % len(config_asset_ids)
-                    self.assign_asset(clip.id, config_asset_ids[asset_idx])
+                    try:
+                        self.assign_asset(clip.id, config_asset_ids[asset_idx])
+                        assigned_count += 1
+                    except Exception as exc:
+                        logger.warning(
+                            "can_generate 最后防线: plan=%s clip=%s 分配素材 %s 失败: %s",
+                            plan_id,
+                            clip.id,
+                            config_asset_ids[asset_idx],
+                            exc,
+                        )
                 logger.info(
-                    "can_generate 最后防线: plan=%s 已为 %d 个片段分配素材",
+                    "can_generate 最后防线: plan=%s 已为 %d/%d 个片段分配素材",
                     plan_id,
+                    assigned_count,
                     len(clips_without_asset),
                 )
                 # 重新加载 clips 验证分配结果