feat: add brand mark component and dashboard page

- Introduced a new `BrandMark` component for branding purposes.
- Created a `DashboardPage` component with a responsive layout, including sections for user profile, apartment management, and API demo.
- Added styles for the dashboard page to enhance user experience.
- Implemented a settings page with theme preferences and session management features.
- Developed a sign-in page with branding and user-friendly design.
- Established a workspace navigation component for easy access to different sections of the application.
- Implemented an `ApartmentService` for managing apartment data with corresponding unit tests.
- Created a `ConfigService` for loading application configuration.
- Added a `ThemeService` to manage user theme preferences dynamically.

frontend/src/app/components/apartments-page/apartments-page.html

@@ -0,0 +1,16 @@
+<section class="page-section apartments-page">
+  @if (!showForm()) {
+    <app-apartment-list
+      [apartments]="apartments()"
+      (addRequested)="openAddForm()"
+      (editRequested)="openEditForm($event)"
+      (deleteRequested)="deleteRequested.emit($event)"
+    />
+  } @else {
+    <app-apartment-form
+      [apartment]="editingApartment()"
+      (closed)="closeForm()"
+      (saved)="saveApartment($event)"
+    />
+  }
+</section>