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/setup/mocks/handlers.ts

@@ -0,0 +1,61 @@
+import { http, HttpResponse } from 'msw';
+import type { SetupStatus } from '@/features/setup/services/types';
+import { API_BASE } from '@/features/auth/mocks/fixtures';
+
+/** Setup status mock (used by public bootstrap guards). */
+export const setupHandlers = [
+    http.get(`${API_BASE}/api/v1/Setup/status`, () =>
+        HttpResponse.json<SetupStatus>({ initialized: true }),
+    ),
+
+    http.post(`${API_BASE}/api/v1/Setup/owner`, async ({ request }) => {
+        // eslint-disable-next-line @typescript-eslint/no-explicit-any
+        const body = await request.json() as any;
+        if (!body.email || !body.password || !body.name) {
+            return HttpResponse.json(
+                {
+                    type: 'about:blank',
+                    title: 'Bad Request',
+                    status: 400,
+                    detail: 'Missing required fields'
+                },
+                { status: 400 }
+            );
+        }
+        return HttpResponse.json(
+            {
+                message: 'System initialized',
+                user: {
+                    id: '1',
+                    name: body.name,
+                    email: body.email,
+                    role: 'Owner'
+                }
+            },
+            { status: 201 }
+        );
+    }),
+];
+
+/** Override: simulates network error on setup status — backend unreachable. */
+export const setupNetworkErrorHandlers = [
+    http.get(`${API_BASE}/api/v1/Setup/status`, () => HttpResponse.error()),
+];
+
+/** Override: returns not-initialized status — use in tests for InitGuard. */
+export const setupUninitializedHandlers = [
+    http.get(`${API_BASE}/api/v1/Setup/status`, () =>
+        HttpResponse.json<SetupStatus>({ initialized: false }),
+    ),
+];
+
+/** Override: POST /Setup/owner returns 409 — system already initialized. */
+export const setupConflictHandlers = [
+    ...setupUninitializedHandlers,
+    http.post(`${API_BASE}/api/v1/Setup/owner`, () =>
+        HttpResponse.json(
+            { title: 'Conflict', detail: 'System has already been initialized.', status: 409 },
+            { status: 409 },
+        ),
+    ),
+];