Add nuxt-skills and update auto quotes to use new policy API structure

- Add nuxt-skills (vue, nuxt, nuxt-ui) to .claude/skills/
- Create useCustomerSelection() composable for managing insured/buyer selection
- Create usePolicyApi() composable for policy API operations
- Update auto quote components to use insured/buyer instead of client
- Update vehicle fields: remove valorVehiculo, add market_value, requested_value, rc_limits
- Make chassis_number and engine_number optional
- Update auto quote types and composables to match new API structure
- Update auto quote page to submit to policy API with new structure

.claude/skills/nuxt-ui/components/page-grid.md

@@ -0,0 +1,11 @@
+# PageGrid
+
+A responsive grid system for displaying content in a flexible layout.
+
+## Usage
+
+```vue
+<UPageGrid
+  <!-- props here -->
+/>
+```