frontend: add workspace context, file content and conflict apis with frontend type contracts

补齐 FE-002：服务端新增 workspace/context、mappings/check-target、files/content、
conflicts 明细与 apply 路由，核心层补充本地文件内容与冲突查询/应用能力及二进制/大文件约束；
前端补齐统一领域类型契约与类型化端点封装。

gradle build / pnpm typecheck 均通过。

Co-authored-by: Cursor <cursoragent@cursor.com>

mactfsui/app/lib/api/index.ts

@@ -1,2 +1,28 @@
-export type { ApiRequestOptions, ApiResponse, ApiResult } from "./types"
+export type {
+  ApiRequestOptions,
+  ApiResponse,
+  ApiResult,
+  AppConfig,
+  CheckMappingTargetResult,
+  CheckinResult,
+  Collection,
+  ConflictInfo,
+  ConflictResolution,
+  ConflictResolutionResult,
+  ConnectResult,
+  FileContent,
+  FileOperationResult,
+  FolderDiffItem,
+  GetLatestResult,
+  HistoryEntry,
+  MappingConfig,
+  MappingInfo,
+  OperationLogEntry,
+  PendingChange,
+  ServerItem,
+  TextDiff,
+  WorkspaceContext,
+  WorkspaceInfo,
+} from "./types"
 export { apiClient } from "./client"
+export * as api from "./endpoints"