feat: add Zod validation schemas for all domain routes

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/schemas/profile.schema.ts

@@ -0,0 +1,11 @@
+import { z } from 'zod';
+
+export const UpdateProfileSchema = z.object({
+  email: z.string().email('Neplatný formát e-mailu').optional(),
+  first_name: z.string().optional(),
+  last_name: z.string().optional(),
+  current_password: z.string().optional(),
+  new_password: z.string().optional(),
+});
+
+export type UpdateProfileInput = z.infer<typeof UpdateProfileSchema>;