feat(recipes): add recipe visibility and sharing features

- Implemented functionality to set recipe visibility (public/private) with appropriate checks for user permissions.
- Added ability to share recipes with other users, including validation for existing users and permissions.
- Introduced new DTOs for setting visibility and sharing recipes.
- Updated RecipesController and RecipesService to handle new endpoints for visibility and sharing.
- Enhanced inventory preview to consider user permissions and shared recipes.
- Updated front-end to support new sharing and visibility features, including UI changes for recipe detail and admin user management.

flutter/lib/features/admin/data/admin_repository.dart

@@ -49,6 +49,19 @@ class AdminRepository {
     return UserAdmin.fromJson(data);
   }
 
+  Future<UserAdmin> setRecipeSharing(int userId, {required bool canShareRecipes}) async {
+    final token = await _token();
+    final data = await guardedApiCall(
+      _ref,
+      () => _apiClient.patchJson(
+        UserApiPaths.setRecipeSharing(userId),
+        body: {'canShareRecipes': canShareRecipes},
+        token: token,
+      ),
+    );
+    return UserAdmin.fromJson(data);
+  }
+
   Future<void> updateEmail(int userId, String email) async {
     final token = await _token();
     await guardedApiCall(