Add price refresh functionality to configurator

- Add price_updated_at field to qt_configurations table to track when prices were last updated
- Add RefreshPrices() method in configuration service to update all component prices with current values from database
- Add POST /api/configs/:uuid/refresh-prices API endpoint for price updates
- Add "Refresh Prices" button in configurator UI next to Save button
- Display last price update timestamp in human-readable format (e.g., "5 min ago", "2 hours ago")
- Create migration 004_add_price_updated_at.sql for database schema update
- Update CLAUDE.md documentation with new API endpoint and schema changes
- Add MIGRATION_PRICE_REFRESH.md with detailed migration instructions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

cmd/server/main.go

@@ -295,6 +295,7 @@ func setupRouter(db *gorm.DB, cfg *config.Config) (*gin.Engine, error) {
 			configs.PUT("/:uuid", configHandler.Update)
 			configs.PATCH("/:uuid/rename", configHandler.Rename)
 			configs.POST("/:uuid/clone", configHandler.Clone)
+			configs.POST("/:uuid/refresh-prices", configHandler.RefreshPrices)
 			configs.DELETE("/:uuid", configHandler.Delete)
 			// configs.GET("/:uuid/export", configHandler.ExportJSON)
 			configs.GET("/:uuid/csv", exportHandler.ExportConfigCSV)