feat: 油价只展示92号、移动端倒数日改两列网格

- 油价格主行只保留 92# 价格，副行只留生效日期（95/98 下线）
- 移动端倒数日从两端对齐改为 50%/50% 两列：标题左、天数右，
  竖线与上方天气/金价、油价/股市列分界 167px 贯通，消除孤立单行突兀感
- 遵守窄屏环境条不截断规则（无 ellipsis），12 字标题上限内不溢出
- 组件测试 3 处油价断言同步

frontend/src/components/TodayEnvironmentStrip.test.ts

@@ -195,8 +195,8 @@ describe('TodayEnvironmentStrip', () => {
     } })
     const oil = host.querySelector('.today-environment__oil')!
     expect(oil.classList.contains('is-fresh')).toBe(true)
-    expect(oil.querySelector('strong')?.textContent).toBe('92# 8.58 · 95# 9.12')
-    expect(oil.querySelector('small')?.textContent).toBe('98# 11.12 · 09-24生效')
+    expect(oil.querySelector('strong')?.textContent).toBe('92# 8.58')
+    expect(oil.querySelector('small')?.textContent).toBe('09-24生效')
     const ashare = host.querySelector('.today-environment__ashare')!
     expect(ashare.querySelector('strong')?.textContent).toBe('上证 3888.37')
     expect(ashare.querySelector('small')?.textContent).toBe('-1.22% · 09-24')
@@ -213,7 +213,7 @@ describe('TodayEnvironmentStrip', () => {
     expect(host.querySelector('.today-environment__ashare small')?.textContent).toBe('+0.35% · 09-25')
     const oil = host.querySelector('.today-environment__oil')!
     expect(oil.classList.contains('is-stale')).toBe(true)
-    expect(oil.querySelector('small')?.textContent).toBe('98# 11.12 · 09-24生效 · 缓存')
+    expect(oil.querySelector('small')?.textContent).toBe('09-24生效 · 缓存')
   })
 
   it('renders unavailable oil and index sources as two-line placeholders', async () => {