feat: Phase 2 — leadership 大屏 (/overview) + district normalization + drawer a11y

Phase 2 of the UX modernization. Three conflict-free workstreams.

Leadership 驾驶舱 (/overview):
- Wuhan 13-district Leaflet choropleth (public/wuhan_districts.geojson, keyed
  on name, darker=higher per 高风险高亮), legend, hover/click-zoom
- 全部/门诊/住院 Segmented toggle drives choropleth + Top-5 district bar
- literal "数据截至2023-12" as-of badge (D3 honesty); raw spinner → LoadingState
- decompose OverviewDashboard 501→273; 6 components + 2 helpers under components/overview/

District normalization (backend data boundary):
- case_loader.normalize_district + load_cases_by_district_daily collapse the
  26 dirty labels (武昌/武昌区…) → 13 canonical; analysis/grid/insights repointed
  (fixes a grid-merge row-drop bug as a bonus); in-memory, schema unchanged

Shell a11y (code-review carryover):
- drawer is now a proper modal: ESC, body scroll-lock, focus-in + focus-trap
  cycle + focus-restore, role=dialog/aria-modal/aria-label, hamburger aria-expanded
- SideNav expanded state lifted to AppShell so rail+drawer stay in sync
- RouteErrorBoundary around <Outlet/> keeps shell chrome on page/chunk failure

Gates: tsc 0 · vitest 64 · e2e 19/19 (17 user-flows + 2 overview) · build ok
· backend pytest 6 new + 48 regression green

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/e2e/overview.spec.ts

@@ -0,0 +1,119 @@
+/**
+ * 综合概览大屏 (/overview) 验收测试。
+ *
+ * 与 user-flows.spec.ts 一致：用 addInitScript 注入 cbpoa_token 绕过登录门，
+ * page.route 拦截 /api/** 使套件 hermetic（无需 :8000）。/wuhan_districts.geojson
+ * 走真实静态资源（dev server 提供），由 Leaflet 取用。
+ */
+import { test, expect, Page } from '@playwright/test';
+import { TESTIDS } from '../src/utils/testids';
+
+/** 13 区里造两条数据，断言 choropleth 能着色、toggle 能切换。 */
+function districtPayload() {
+  return {
+    districts: [
+      { district: '武昌区', outpatient: 120, inpatient: 30, total: 150, outpatient_ratio: 0.8, inpatient_ratio: 0.2 },
+      { district: '江岸', outpatient: 60, inpatient: 10, total: 70, outpatient_ratio: 0.86, inpatient_ratio: 0.14 },
+    ],
+    total: 220,
+  };
+}
+
+async function seedAuthAndMockApi(page: Page) {
+  await page.addInitScript(() => {
+    localStorage.setItem('cbpoa_token', 'e2e-test-token');
+  });
+
+  await page.route('/api/**', (route) => {
+    const url = route.request().url();
+
+    const json = (body: unknown) =>
+      route.fulfill({ status: 200, contentType: 'application/json', body: JSON.stringify(body) });
+
+    if (url.includes('/alerts')) {
+      return json({ alerts: [], total: 0 });
+    }
+    if (url.includes('/cases/stats')) {
+      return json({
+        total_outpatient: 1000,
+        total_inpatient: 200,
+        date_range: { start: '2023-01-01', end: '2023-12-01' },
+        top_districts: [],
+        top_diagnoses: [
+          { diagnosis: '上呼吸道感染', outpatient: 300, inpatient: 40 },
+          { diagnosis: '肺炎', outpatient: 120, inpatient: 80 },
+        ],
+      });
+    }
+    if (url.includes('/cases/trend')) {
+      return json({
+        trend: [
+          { date: '2023-11-01', outpatient: 10, inpatient: 2, total: 12 },
+          { date: '2023-11-02', outpatient: 14, inpatient: 3, total: 17 },
+        ],
+        summary: {
+          total_outpatient: 24,
+          total_inpatient: 5,
+          period_count: 2,
+          avg_daily_outpatient: 12,
+          avg_daily_inpatient: 2.5,
+        },
+      });
+    }
+    if (url.includes('/cases/districts')) {
+      return json(districtPayload());
+    }
+    if (url.includes('/risk/stats')) {
+      return json({ high_risk_count: 7, total_grids: 100, avg_risk: 0.4 });
+    }
+    if (url.includes('/environment/pollutants')) {
+      return json({ data: [{ date: '2023-11-01', AQI: 80 }, { date: '2023-11-02', AQI: 95 }] });
+    }
+
+    return json({ data: [], items: [], total: 0 });
+  });
+}
+
+test.describe('Overview 大屏', () => {
+  test.use({ viewport: { width: 1280, height: 900 } });
+
+  test.beforeEach(async ({ page }) => {
+    await seedAuthAndMockApi(page);
+  });
+
+  test('renders kpi-row, choropleth, as-of badge and metric toggle', async ({ page }) => {
+    await page.goto('/overview');
+
+    await expect(page.locator(`[data-testid="${TESTIDS.pageOverview}"]`)).toBeVisible();
+    await expect(page.locator(`[data-testid="${TESTIDS.kpiRow}"]`)).toBeVisible();
+    await expect(page.locator(`[data-testid="${TESTIDS.choroplethWrapper}"]`)).toBeVisible();
+
+    // Literal honesty badge — exact text.
+    const badge = page.locator(`[data-testid="${TESTIDS.asofBadge}"]`);
+    await expect(badge).toBeVisible();
+    await expect(badge).toHaveText('数据截至2023-12');
+  });
+
+  test('门诊/住院 toggle switches active segment without error', async ({ page }) => {
+    await page.goto('/overview');
+    await expect(page.locator(`[data-testid="${TESTIDS.choroplethWrapper}"]`)).toBeVisible();
+
+    const outBtn = page.locator(`[data-testid="${TESTIDS.outinpatientToggle}-outpatient"]`);
+    const inBtn = page.locator(`[data-testid="${TESTIDS.outinpatientToggle}-inpatient"]`);
+    const allBtn = page.locator(`[data-testid="${TESTIDS.outinpatientToggle}-all"]`);
+
+    // Default: 全部 active (primary background).
+    await expect(allBtn).toHaveClass(/bg-primary/);
+
+    await outBtn.click();
+    await expect(outBtn).toHaveClass(/bg-primary/);
+    await expect(allBtn).not.toHaveClass(/bg-primary/);
+
+    await inBtn.click();
+    await expect(inBtn).toHaveClass(/bg-primary/);
+    await expect(outBtn).not.toHaveClass(/bg-primary/);
+
+    // Wrapper still mounted after toggling — no render crash.
+    await expect(page.locator(`[data-testid="${TESTIDS.choroplethWrapper}"]`)).toBeVisible();
+  });
+});