feat: update docs for token efficient usage

frontend/src/features/CLAUDE.md

@@ -0,0 +1,19 @@
+# frontend/src/features/
+
+Feature module directory. Each feature contains pages/, components/, hooks/, api/, types/.
+
+## Subdirectories
+
+| Directory | What | When to read |
+| --------- | ---- | ------------ |
+| `admin/` | Admin panel and catalog management | Admin UI, user management |
+| `auth/` | Authentication pages and components | Login, logout, auth flows |
+| `dashboard/` | Dashboard and fleet overview | Home page, summary widgets |
+| `documents/` | Document management UI | File upload, document viewer |
+| `fuel-logs/` | Fuel log tracking UI | Fuel entry forms, statistics |
+| `maintenance/` | Maintenance record UI | Service tracking, reminders |
+| `notifications/` | Notification display | Alert UI, notification center |
+| `onboarding/` | Onboarding wizard | First-time user experience |
+| `settings/` | User settings pages | Preferences, account settings |
+| `stations/` | Gas station finder UI | Station search, favorites, map |
+| `vehicles/` | Vehicle management UI | Vehicle list, details, forms |