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/cms/schemas/cms.ts

@@ -0,0 +1,25 @@
+import { z } from 'zod';
+
+export const addCmsInstanceSchema = z.object({
+    name: z.string().min(1, 'Name is required').max(255, 'Name must be 255 characters or fewer'),
+    url: z.string().url('Must be a valid URL (include http:// or https://)'),
+    apiKey: z.string().min(1, 'API key is required'),
+});
+
+export type AddCmsInstanceFormData = z.infer<typeof addCmsInstanceSchema>;
+
+export const setStatusSchema = z
+    .object({
+        status: z.enum(['Available', 'NotAvailable', 'Inactive']),
+        disableMessage: z.string().optional(),
+    })
+    .refine(
+        (data) =>
+            data.status !== 'NotAvailable' || (data.disableMessage?.trim().length ?? 0) > 0,
+        {
+            message: 'Disable message is required when status is Not Available',
+            path: ['disableMessage'],
+        },
+    );
+
+export type SetStatusFormData = z.infer<typeof setStatusSchema>;