improvement: some files replaced, lots of them i shall say. AGENT.MD file created. some rules and skills added for cursor agent.

.cursor/rules/frontend-components.mdc

@@ -0,0 +1,47 @@
+---
+description: Frontend folder structure — ui vs non-ui, thin pages, feature layout
+globs: frontend/src/**
+alwaysApply: false
+---
+
+# Frontend component structure
+
+## Rules
+
+| Kind | Location |
+|------|----------|
+| Cross-feature UI | `components/ui/shared/` |
+| Feature UI | `components/ui/{feature}/` |
+| Cross-feature non-UI | `components/shared/` |
+| Feature non-UI | `components/{feature}/` |
+| Route logic | `components/ui/{feature}/{Feature}Page.tsx` |
+| App routes | `app/**/page.tsx` — **thin wrapper only** |
+
+## Thin page pattern
+
+```tsx
+'use client';
+import { PatientsPage } from '@/components/ui/patient/PatientsPage';
+export default function Page() {
+  return <PatientsPage />;
+}
+```
+
+Reference: `app/.../treatment/page.tsx` + `components/ui/treatment/TreatmentWorkspace.tsx`.
+
+## Do not
+
+- Put React components (`.tsx` with JSX) in `components/` outside `ui/`.
+- Put pure helpers (`.ts`, no JSX) inside `components/ui/`.
+- Put business logic, API calls, or large forms directly in `app/**/page.tsx`.
+
+## API & errors
+
+- API clients: `lib/api/`.
+- Catch blocks: `getUserFacingError(err, tErrors, fallback)` from `components/shared/formatApiError.ts`.
+
+## When adding UI
+
+1. Check `components/ui/shared/` for an existing primitive.
+2. Check the feature's `ui/{feature}/` folder for an existing pattern.
+3. Add i18n keys to en, fa, and nl.