feat: update docs for token efficient usage

frontend/src/CLAUDE.md

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+# frontend/src/
+
+## Files
+
+| File | What | When to read |
+| ---- | ---- | ------------ |
+| `App.tsx` | Root component with routing | Route configuration, layout structure |
+| `main.tsx` | Application entry point | Provider setup, initialization |
+| `index.css` | Global styles | Base styling, CSS imports |
+| `vite-env.d.ts` | Vite type definitions | TypeScript environment types |
+
+## Subdirectories
+
+| Directory | What | When to read |
+| --------- | ---- | ------------ |
+| `features/` | Feature modules (pages, components, hooks) | Feature development |
+| `core/` | Shared infrastructure (auth, api, store) | Cross-cutting concerns |
+| `components/` | Root-level shared components | App-wide UI components |
+| `pages/` | Page-level components | Page structure, routing targets |
+| `shared-minimal/` | Minimal shared UI (skeletons, theme) | Reusable UI primitives |

frontend/src/core/CLAUDE.md

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+# frontend/src/core/
+
+## Subdirectories
+
+| Directory | What | When to read |
+| --------- | ---- | ------------ |
+| `api/` | API client and request handling | HTTP calls, error handling |
+| `auth/` | Auth0 provider and auth hooks | Authentication setup, user context |
+| `config/` | Runtime configuration | Environment-specific settings |
+| `debug/` | Debug utilities | Development helpers |
+| `error-boundaries/` | React error boundaries | Error handling UI |
+| `hooks/` | Shared React hooks | Reusable hook patterns |
+| `query/` | React Query configuration | Server state management |
+| `store/` | Zustand state management | Client state, global stores |
+| `sync/` | Data synchronization | Offline support, sync logic |
+| `units/` | Unit conversion utilities | Measurement formatting |
+| `utils/` | General utilities | Helper functions |

frontend/src/features/CLAUDE.md

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+# 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 |