refactor(api): 统一响应格式迁移 + 异步任务系统 + 状态码体系完善

- 将全部路由文件（12个）的 jsonify 响应迁移至 success_response/error_response 统一格式
- 修复 sync_routes.py error_response 参数错误（P0）
- 新增异步任务系统：task_registry + task_routes
- 新增状态码：TASK_NOT_FOUND(4014)、TASK_CONFLICT(4015)、REINDEX_ERROR(5040)
- 修正 task_routes/exam_pkg 中语义不匹配的状态码
- 更新 curl 测试手册、后端对接规范文档
- 添加缓存性能报告和 Redis 迁移计划

api/chat_routes.py

@@ -37,6 +37,8 @@ import logging
 
 logger = logging.getLogger(__name__)
 from auth.gateway import require_gateway_auth
+from core.status_codes import SUCCESS, BAD_REQUEST, NOT_FOUND, INTERNAL_ERROR
+from api.response_utils import success_response, error_response
 
 from auth.security import validate_query, filter_response
 from config import RAG_CHAT_MODEL
@@ -1238,12 +1240,12 @@ def chat():
     history = data.get('history', [])
 
     if not message:
-        return jsonify({"error": "缺少 message"}), 400
+        return error_response("MISSING_PARAMS", BAD_REQUEST, "缺少 message", http_status=400)
 
     # 输入安全验证
     is_valid, reason = validate_query(message)
     if not is_valid:
-        return jsonify({"error": reason}), 400
+        return error_response("INVALID_QUERY", BAD_REQUEST, reason, http_status=400)
 
     # 智能聊天
     result = chat_with_llm(message, history)
@@ -1251,7 +1253,7 @@ def chat():
     # 过滤敏感信息
     answer = filter_response(result["answer"])
 
-    return jsonify({
+    return success_response(data={
         "answer": answer,
         "mode": "chat",
         "sources": result.get("sources", []),
@@ -1309,19 +1311,16 @@ def rag():
     session_id = data.get('session_id')
 
     if not message:
-        return jsonify({"error": "缺少 message"}), 400
+        return error_response("MISSING_PARAMS", BAD_REQUEST, "缺少 message", http_status=400)
 
     # 生产环境强制校验 chat_history
     if IS_PROD and history is None:
-        return jsonify({
-            "error": "chat_history is required in production",
-            "code": "MISSING_HISTORY"
-        }), 400
+        return error_response("MISSING_HISTORY", BAD_REQUEST, "chat_history is required in production", http_status=400)
 
     # 输入安全验证
     is_valid, reason = validate_query(message)
     if not is_valid:
-        return jsonify({"error": reason}), 400
+        return error_response("INVALID_QUERY", BAD_REQUEST, reason, http_status=400)
 
     # 如果没有指定 collections，使用默认的公开库
     if not collections:
@@ -2048,12 +2047,12 @@ def search():
     collections = data.get('collections')  # 后端传入的知识库列表
 
     if not query:
-        return jsonify({'error': 'query is required'}), 400
+        return error_response("MISSING_PARAMS", BAD_REQUEST, "query is required", http_status=400)
 
     # 输入安全校验（注入检测、违禁词、长度限制）
     is_valid, reason = validate_query(query)
     if not is_valid:
-        return jsonify({'error': reason}), 400
+        return error_response("INVALID_QUERY", BAD_REQUEST, reason, http_status=400)
 
     # top_k 范围校验
     try:
@@ -2067,7 +2066,7 @@ def search():
 
     results = search_hybrid(query, top_k=top_k, allowed_collections=collections)
 
-    return jsonify({
+    return success_response(data={
         'contexts': results['documents'][0],
         'metadatas': results['metadatas'][0],
         'scores': results['scores'][0]