Restructures frontend to a feature-based folder layout

Groups auth, setup, invitation, profile, users, cms, availability and
system code (services/hooks, components, schemas, mocks, pages) under
src/features/<name> instead of splitting by technical layer (api/,
components/, lib/schemas/, mocks/, pages/). Renames the old
connection-oriented `api` layer to `services` per feature, and splits
the monolithic api/types.ts into per-feature types.ts files (with
ProblemDetails/ApiResult merged into lib/api-client.ts as shared
infra). Layout-agnostic code (ui primitives, app shell, i18n, test
utils, lib) stays at the top level.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

frontend/src/features/auth/schemas/auth.test.ts

@@ -0,0 +1,122 @@
+import { describe, expect, it } from 'vitest';
+import {
+    passwordSchema,
+    setupFormSchema,
+    loginFormSchema,
+    invitationCompleteFormSchema,
+} from '@/features/auth/schemas/auth';
+
+describe('passwordSchema', () => {
+    it('accepts a valid password', () => {
+        expect(passwordSchema.safeParse('Password1!').success).toBe(true);
+    });
+
+    it('rejects a password that is too short', () => {
+        expect(passwordSchema.safeParse('Pass1!').success).toBe(false);
+    });
+
+    it('rejects a password without an uppercase letter', () => {
+        expect(passwordSchema.safeParse('password1!').success).toBe(false);
+    });
+
+    it('rejects a password without a digit', () => {
+        expect(passwordSchema.safeParse('Password!').success).toBe(false);
+    });
+
+    it('rejects a password without a special character', () => {
+        expect(passwordSchema.safeParse('Password1').success).toBe(false);
+    });
+});
+
+describe('setupFormSchema', () => {
+    const valid = {
+        name: 'Admin',
+        email: 'admin@example.com',
+        password: 'Password1!',
+        confirmPassword: 'Password1!',
+        language: 'nl' as const,
+    };
+
+    it('accepts valid setup data', () => {
+        expect(setupFormSchema.safeParse(valid).success).toBe(true);
+    });
+
+    it('rejects when passwords do not match', () => {
+        const result = setupFormSchema.safeParse({ ...valid, confirmPassword: 'Different1!' });
+        expect(result.success).toBe(false);
+    });
+
+    it('rejects empty name', () => {
+        expect(setupFormSchema.safeParse({ ...valid, name: '' }).success).toBe(false);
+    });
+
+    it('rejects name exceeding 255 characters', () => {
+        expect(setupFormSchema.safeParse({ ...valid, name: 'a'.repeat(256) }).success).toBe(false);
+    });
+
+    it('rejects invalid email format', () => {
+        expect(setupFormSchema.safeParse({ ...valid, email: 'not-an-email' }).success).toBe(false);
+    });
+
+    it('rejects empty email', () => {
+        expect(setupFormSchema.safeParse({ ...valid, email: '' }).success).toBe(false);
+    });
+
+    it('rejects invalid language', () => {
+        expect(setupFormSchema.safeParse({ ...valid, language: 'fr' }).success).toBe(false);
+    });
+
+    it('accepts "en" as language', () => {
+        expect(setupFormSchema.safeParse({ ...valid, language: 'en' }).success).toBe(true);
+    });
+});
+
+describe('loginFormSchema', () => {
+    it('accepts valid login credentials', () => {
+        expect(loginFormSchema.safeParse({ email: 'user@example.com', password: 'anypass' }).success).toBe(true);
+    });
+
+    it('rejects empty email', () => {
+        expect(loginFormSchema.safeParse({ email: '', password: 'pass' }).success).toBe(false);
+    });
+
+    it('rejects invalid email format', () => {
+        expect(loginFormSchema.safeParse({ email: 'not-email', password: 'pass' }).success).toBe(false);
+    });
+
+    it('rejects empty password', () => {
+        expect(loginFormSchema.safeParse({ email: 'user@example.com', password: '' }).success).toBe(false);
+    });
+});
+
+describe('invitationCompleteFormSchema', () => {
+    const valid = {
+        name: 'New User',
+        password: 'Password1!',
+        confirmPassword: 'Password1!',
+    };
+
+    it('accepts valid invitation completion data', () => {
+        expect(invitationCompleteFormSchema.safeParse(valid).success).toBe(true);
+    });
+
+    it('rejects when passwords do not match', () => {
+        expect(
+            invitationCompleteFormSchema.safeParse({ ...valid, confirmPassword: 'Different1!' }).success,
+        ).toBe(false);
+    });
+
+    it('rejects empty name', () => {
+        expect(invitationCompleteFormSchema.safeParse({ ...valid, name: '' }).success).toBe(false);
+    });
+
+    it('rejects weak password', () => {
+        expect(
+            invitationCompleteFormSchema.safeParse({
+                ...valid,
+                password: 'weak',
+                confirmPassword: 'weak',
+            }).success,
+        ).toBe(false);
+    });
+});