safe: 安全升级（不影响飞书/Pipeline/Redis）

- bcrypt 密码哈希升级（兼容旧 SHA-256，登录时自动升级）
- auth_manager.secret_key 从环境变量读取
- 前端事件总线（on/off/emit）
- ConfigService 统一配置服务
- AI 监控错误详情修复（Conversation 没有 category/source）
- README.md 重写

src/config/config_service.py

@@ -0,0 +1,76 @@
+# -*- coding: utf-8 -*-
+"""
+统一配置服务
+优先级：环境变量 > system_settings.json > 代码默认值
+"""
+import os
+import json
+import logging
+from typing import Any
+
+logger = logging.getLogger(__name__)
+_SETTINGS_PATH = os.path.join('data', 'system_settings.json')
+
+
+class ConfigService:
+    def __init__(self):
+        self._file_cache = None
+        self._file_mtime = 0
+
+    def _load_file(self) -> dict:
+        try:
+            if os.path.exists(_SETTINGS_PATH):
+                mtime = os.path.getmtime(_SETTINGS_PATH)
+                if mtime != self._file_mtime or self._file_cache is None:
+                    with open(_SETTINGS_PATH, 'r', encoding='utf-8') as f:
+                        self._file_cache = json.load(f)
+                    self._file_mtime = mtime
+                return self._file_cache or {}
+        except Exception as e:
+            logger.debug(f"加载配置文件失败: {e}")
+        return {}
+
+    def get(self, key: str, default: Any = None) -> Any:
+        env_key = key.upper().replace('.', '_')
+        env_val = os.environ.get(env_key)
+        if env_val is not None:
+            return self._cast(env_val, default)
+        settings = self._load_file()
+        parts = key.split('.')
+        val = settings
+        for part in parts:
+            if isinstance(val, dict):
+                val = val.get(part)
+            else:
+                return default
+        return val if val is not None else default
+
+    def get_section(self, section: str) -> dict:
+        return self._load_file().get(section, {})
+
+    def set(self, key: str, value: Any):
+        settings = self._load_file()
+        parts = key.split('.')
+        target = settings
+        for part in parts[:-1]:
+            target = target.setdefault(part, {})
+        target[parts[-1]] = value
+        os.makedirs('data', exist_ok=True)
+        with open(_SETTINGS_PATH, 'w', encoding='utf-8') as f:
+            json.dump(settings, f, ensure_ascii=False, indent=2)
+        self._file_cache = settings
+
+    @staticmethod
+    def _cast(value: str, default: Any) -> Any:
+        if default is None: return value
+        if isinstance(default, bool): return value.lower() in ('true', '1', 'yes')
+        if isinstance(default, int):
+            try: return int(value)
+            except: return default
+        if isinstance(default, float):
+            try: return float(value)
+            except: return default
+        return value
+
+
+config_service = ConfigService()