feat(frontend): optimize gemini setup ui and usage visualization

- refactor: clarify gemini auth types (Built-in vs Custom)
- feat: add setup guide with checklist and official links
- feat: display simulated daily quota progress bar
- style: apply brand-aligned colors (Blue/Gray) to gemini sections

frontend/src/types/index.ts

@@ -382,6 +382,8 @@ export interface AccountUsageInfo {
   five_hour: UsageProgress | null
   seven_day: UsageProgress | null
   seven_day_sonnet: UsageProgress | null
+  gemini_pro_daily?: UsageProgress | null
+  gemini_flash_daily?: UsageProgress | null
 }
 
 // OpenAI Codex usage snapshot (from response headers)