Initial commit: @b2c/first_page HarmonyOS stage-mode HAR

## Repository
- HarmonyOS stage-mode HAR module, consumed by host app
- No standalone build — hvigorw, oh_modules, and ../biz_quote absent here

## Architecture
### Feed Cards
- FirstPage.createNodeView dispatches cards by FirstPageConstant.KEY_*
- Card config from first_page_cards_config.json loaded by FirstPageCardsConfigLoader
- Public entrypoint: Index.ets

### Market Ranking (src/main/ets/market-ranking/)
- HTTP: MarketRankingDataFetcher fetches recommend_futures contracts
- HQ: MarketRankingHqRequestClient subscribes via 4106/frame 2201/scenario qht_qihuo_sort
- TCP reconnect rebuilds subscription from original HTTP contract list
- Async callbacks guarded by request/subscription versions

### Other Cards
- HotList, CommodityOptions, AiDiagnosis, AiRiseFall, SelfSelectedStock, CustomEntryList, FourEntryList
- Each has DataFetcher + HQ request client + NodeComponent

## Key Changes (from CardHarmonyOS reference)
- Added MetricId, PeriodId, SortOrder enums (MarketRankingModels.ets)
- Replaced string comparisons with enum switches in thirdColumnTitle/Value/Color
- Removed redundant undefined guards in thirdColumnColor/priceColor, delegated to riseFallColor
- Inlined priceColor(), use riseFallColor directly
- Tab bar Stack.height(30), Alignment.End (reverted from 46/TopEnd)
- Name column fontWeight removed (default regular)

src/test/List.test.ets

@@ -0,0 +1,5 @@
+import localUnitTest from './LocalUnit.test';
+
+export default function testsuite() {
+  localUnitTest();
+}

src/test/LocalUnit.test.ets

@@ -0,0 +1,33 @@
+import { describe, beforeAll, beforeEach, afterEach, afterAll, it, expect } from '@ohos/hypium';
+
+export default function localUnitTest() {
+  describe('localUnitTest', () => {
+    // Defines a test suite. Two parameters are supported: test suite name and test suite function.
+    beforeAll(() => {
+      // Presets an action, which is performed only once before all test cases of the test suite start.
+      // This API supports only one parameter: preset action function.
+    });
+    beforeEach(() => {
+      // Presets an action, which is performed before each unit test case starts.
+      // The number of execution times is the same as the number of test cases defined by **it**.
+      // This API supports only one parameter: preset action function.
+    });
+    afterEach(() => {
+      // Presets a clear action, which is performed after each unit test case ends.
+      // The number of execution times is the same as the number of test cases defined by **it**.
+      // This API supports only one parameter: clear action function.
+    });
+    afterAll(() => {
+      // Presets a clear action, which is performed after all test cases of the test suite end.
+      // This API supports only one parameter: clear action function.
+    });
+    it('assertContain', 0, () => {
+      // Defines a test case. This API supports three parameters: test case name, filter parameter, and test case function.
+      let a = 'abc';
+      let b = 'b';
+      // Defines a variety of assertion methods, which are used to declare expected boolean conditions.
+      expect(a).assertContain(b);
+      expect(a).assertEqual(a);
+    });
+  });
+}