refactor(core): distinguish network errors from auth failures and refactor real-time messaging pipeline

- Add isNetworkError() helper and FetchCurrentUserResult discriminated union to prevent logout on network failures
- Refactor authService to return { kind: 'user' } | { kind: 'auth_failed' } | { kind: 'network_error' }
- Update authStore to preserve login state on network errors, only logout on auth failures
- Replace WSMessageHandler with RealtimeIngestionPipeline for improved real-time message handling
- Remove MessageDeduplication service; add store-level idempotent addOrReplaceMessage for message dedup
- Add atomic systemUnreadCount operations to prevent race conditions
- Add SearchHeader component for consistent search UI across screens
- Add 'home' TabBar variant with underline style matching HomeScreen
- Add Jest test infrastructure and exclude tests from tsconfig
- Fix ChatScreen history lock being stuck when scrolling to latest messages
- Remove unused call_participant_joined/left WS event types

jest.config.js

@@ -0,0 +1,46 @@
+/**
+ * Jest 配置
+ *
+ * 仅对消息状态核心逻辑（store 幂等性 / 实时事件管道 / 未读计数原子性）做单测，
+ * 不覆盖 RN / Expo UI。所有平台依赖（@/services/core、@/database、@/core/events、
+ * @/stores/auth、@/services/message）在测试中通过 moduleNameMapper 映射到 mock。
+ */
+const { pathsToModuleNameMapper } = require('ts-jest');
+
+const tsconfig = require('./tsconfig.json');
+const tsconfigBase = require('expo/tsconfig.base.json');
+
+// 合并 base + 项目 paths
+const paths = {
+  ...(tsconfigBase.compilerOptions.paths || {}),
+  ...(tsconfig.compilerOptions.paths || {}),
+};
+
+module.exports = {
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+  roots: ['<rootDir>/src'],
+  testMatch: ['**/__tests__/**/*.test.ts'],
+  moduleNameMapper: {
+    // 平台依赖统一映射到 mock（必须放在 @/* 通配之前，否则会被通配吞掉）
+    '^@/services/core$': '<rootDir>/src/stores/message/__tests__/mocks/coreMock.ts',
+    '^@/services/message$': '<rootDir>/src/stores/message/__tests__/mocks/messageServiceMock.ts',
+    '^@/database$': '<rootDir>/src/stores/message/__tests__/mocks/databaseMock.ts',
+    '^@/core/events/EventBus$': '<rootDir>/src/stores/message/__tests__/mocks/eventBusMock.ts',
+    '^@/stores/auth/authStore$': '<rootDir>/src/stores/message/__tests__/mocks/authStoreMock.ts',
+    '^@react-native-async-storage/async-storage$':
+      '<rootDir>/src/stores/message/__tests__/mocks/asyncStorageMock.ts',
+    // @/* 路径别名 → 真实 src（通配兜底，放最后）
+    ...pathsToModuleNameMapper(paths, { prefix: '<rootDir>/' }),
+  },
+  transform: {
+    '^.+\\.tsx?$': [
+      'ts-jest',
+      {
+        tsconfig: '<rootDir>/src/stores/message/__tests__/tsconfig.json',
+        isolatedModules: true,
+      },
+    ],
+  },
+  clearMocks: true,
+};