feat(pos): add shop and statistics modules with components, services, and routing

- Implemented shop module with root component, loading state, and invoice handling.
- Created statistics module with invoice type card component, API routes, and data models.
- Added season picker component for selecting year and season.
- Integrated services for fetching statistics data and managing state.
- Established routing for statistics and shop views.

src/app/shared/components/seasonPicker/season-picker.component.html

@@ -0,0 +1,18 @@
+<div class="flex items-center gap-2 overflow-hidden rounded-xl border border-slate-200 bg-white p-2">
+  <p-button icon="pi pi-chevron-right" size="small" text class="shrink-0" (onClick)="prevSeason()" />
+  <div class="flex flex-1 cursor-pointer justify-center" (click)="openPicker()">
+    <span class="text-base font-semibold">{{ currentSeason() }}</span>
+  </div>
+  <p-button icon="pi pi-chevron-left" size="small" text class="shrink-0" (onClick)="nextSeason()" />
+</div>
+
+@if (isOpen()) {
+  <season-picker-dialog
+    [visible]="isOpen()"
+    [years]="years()"
+    [seasons]="seasons"
+    [selectedYear]="selectedYear()"
+    [selectedSeason]="selectedSeason()"
+    (visibleChange)="isOpen.set($event)"
+    (submit)="submitPicker($event)" />
+}