fix(usage): 移动端缓存 token 拆分为读/写两列展示

cache_read 与 cache_creation 原本被合并为单值，现分别显示并补充测试

frontend/src/features/usage/__tests__/token-normalization.spec.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest'
 
-import { getCacheCreationTokens, getEffectiveInputTokens } from '../token-normalization'
+import { getCacheCreationTokens, getCacheReadTokens, getEffectiveInputTokens } from '../token-normalization'
 
 describe('usage token normalization', () => {
   it('prefers explicit cache creation totals when present', () => {
@@ -19,6 +19,20 @@ describe('usage token normalization', () => {
     })).toBe(20)
   })
 
+  it('keeps cache read and cache creation as separate display values', () => {
+    const usage = {
+      input_tokens: 1,
+      cache_creation_input_tokens: 1530,
+      cache_read_input_tokens: 104026,
+      output_tokens: 591,
+      api_format: 'claude:chat',
+    }
+
+    expect(getEffectiveInputTokens(usage)).toBe(1)
+    expect(getCacheReadTokens(usage)).toBe(104026)
+    expect(getCacheCreationTokens(usage)).toBe(1530)
+  })
+
   it('keeps effective input token normalization unchanged', () => {
     expect(getEffectiveInputTokens({
       input_tokens: 100,