fix: update Claude usage window to support 4.6 models

The usage progress bar only matched claude-sonnet-4-5 and
claude-opus-4-5-thinking. After upgrading to 4.6, the backend returns
claude-sonnet-4-6/claude-opus-4-6-thinking which didn't match,
causing the Claude usage bar to not display.

- Add claude-sonnet-4-6 and claude-opus-4-6-thinking to the match list
- Rename label from "C4.5" to "Claude" for future-proofing

frontend/src/components/account/AccountUsageCell.vue

@@ -172,12 +172,12 @@
           color="purple"
         />
 
-        <!-- Claude 4.5 -->
+        <!-- Claude -->
         <UsageProgressBar
-          v-if="antigravityClaude45UsageFromAPI !== null"
-          :label="t('admin.accounts.usageWindow.claude45')"
-          :utilization="antigravityClaude45UsageFromAPI.utilization"
-          :resets-at="antigravityClaude45UsageFromAPI.resetTime"
+          v-if="antigravityClaudeUsageFromAPI !== null"
+          :label="t('admin.accounts.usageWindow.claude')"
+          :utilization="antigravityClaudeUsageFromAPI.utilization"
+          :resets-at="antigravityClaudeUsageFromAPI.resetTime"
           color="amber"
         />
       </div>
@@ -400,9 +400,12 @@ const antigravity3FlashUsageFromAPI = computed(() => getAntigravityUsageFromAPI(
 // Gemini 3 Image from API
 const antigravity3ImageUsageFromAPI = computed(() => getAntigravityUsageFromAPI(['gemini-3-pro-image']))
 
-// Claude 4.5 from API
-const antigravityClaude45UsageFromAPI = computed(() =>
-  getAntigravityUsageFromAPI(['claude-sonnet-4-5', 'claude-opus-4-5-thinking'])
+// Claude from API (all Claude model variants)
+const antigravityClaudeUsageFromAPI = computed(() =>
+  getAntigravityUsageFromAPI([
+    'claude-sonnet-4-5', 'claude-opus-4-5-thinking',
+    'claude-sonnet-4-6', 'claude-opus-4-6-thinking',
+  ])
 )
 
 // Antigravity 账户类型（从 load_code_assist 响应中提取）

frontend/src/i18n/locales/en.ts

@@ -2047,7 +2047,7 @@ export default {
         gemini3Pro: 'G3P',
         gemini3Flash: 'G3F',
         gemini3Image: 'G3I',
-        claude45: 'C4.5'
+        claude: 'Claude'
       },
       tier: {
         free: 'Free',

frontend/src/i18n/locales/zh.ts

@@ -1583,7 +1583,7 @@ export default {
         gemini3Pro: 'G3P',
         gemini3Flash: 'G3F',
         gemini3Image: 'G3I',
-        claude45: 'C4.5'
+        claude: 'Claude'
       },
       tier: {
         free: 'Free',