feat(rules): 条件系统增强，支持 all/any 组合条件和 original/current 数据源切换

- evaluate_condition 支持递归 all/any 组合节点和 source 字段
- header_rules 支持 condition 条件触发，HeaderBuilder.apply_rules 透传 body/original_body
- 提取 EndpointConditionEditor 组件统一请求头/请求体规则的条件编辑 UI
- header_rules 新增服务端结构校验（action/key/from/to/condition）
- 新增组合条件、source 切换、fail-closed 等测试用例

frontend/src/api/endpoints/types/provider.ts

@@ -42,8 +42,6 @@ export interface HeaderRuleRename {
   to: string
 }
 
-export type HeaderRule = HeaderRuleSet | HeaderRuleDrop | HeaderRuleRename
-
 /**
  * 请求体规则类型
  * - set: 设置/覆盖字段
@@ -136,10 +134,28 @@ export type BodyRuleConditionOp =
   | 'exists' | 'not_exists'
   | 'in' | 'type_is'
 
-export interface BodyRuleCondition {
+export interface BodyRuleConditionLeaf {
   path: string
   op: BodyRuleConditionOp
   value?: unknown  // exists / not_exists 不需要 value
+  source?: 'original' | 'current'
+}
+
+export interface BodyRuleConditionAll {
+  all: BodyRuleCondition[]
+}
+
+export interface BodyRuleConditionAny {
+  any: BodyRuleCondition[]
+}
+
+export type BodyRuleCondition =
+  | BodyRuleConditionLeaf
+  | BodyRuleConditionAll
+  | BodyRuleConditionAny
+
+export type HeaderRule = (HeaderRuleSet | HeaderRuleDrop | HeaderRuleRename) & {
+  condition?: BodyRuleCondition
 }
 
 /**