feat(pricing): introduce real-time budget estimator

This commit introduces a real-time budget estimator for event services. A new summary sidebar now displays a live,
itemized breakdown of costs as the user selects options in the order form.

Key changes include:
- A new `OrderSummary` component to display the price breakdown and total.
- Comprehensive pricing logic implemented in the `useEventOrder` composable.
- A responsive two-column layout on the main page to accommodate the summary.
- UI/UX improvements across the form, including clearer labels and subtle transition animations for conditional fields.

package.json

@@ -15,5 +15,8 @@
     "typescript": "^5.9.3",
     "vue": "^3.5.22",
     "vue-router": "^4.5.1"
+  },
+  "devDependencies": {
+    "@iconify-json/lucide": "^1.2.69"
   }
 }