feat: add expenses module, restaurant mode, and dynamic sales filters

- Gastos (Expenses): Added `/gastos` route, auto-creation of `expenses` DB table, and `gastos.html` to track net profit with split month/year dropdowns.
- Sales & Filters: Overhauled `/sales` backend to use pagination. Top summary cards now accurately reflect the selected payment method filter.
- Checkout Improvements:
  - Added "Transferencia" as a payment option with numpad shortcuts.
  - Built a "Pinned Products" quick-access grid using localStorage.
  - Implemented a global processing lock to prevent duplicate sales on double-clicks.
  - Burned the default HTML number arrows with custom CSS.
- Global Settings & Receipts:
  - Created a global settings modal accessible from the navbar.
  - Added localStorage toggles for custom business name and auto-print.
  - Added "Restaurant Mode" toggle to prompt for Client Name and Pickup Time, which now dynamically prints on the receipt.
- Bug Fixes: Resolved Jinja `TemplateSyntaxError` crash and removed the duplicate search bar in the checkout view.

templates/macros/base.html

@@ -21,7 +21,11 @@
     <main class="container-fluid px-3">
         {% block content %}{% endblock %}
     </main>
+    
+    {% from 'macros/modals.html' import settings_modal %}
+    {{ settings_modal() }}
 
+    
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js"></script>
     <script src="{{ url_for('static', filename='cookieStuff.js') }}"></script>
     <script src="{{ url_for('static', filename='themeStuff.js') }}"></script>