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>

internal/handlers/configuration.go

@@ -181,6 +181,25 @@ func (h *ConfigurationHandler) Clone(c *gin.Context) {
 	c.JSON(http.StatusCreated, config)
 }
 
+func (h *ConfigurationHandler) RefreshPrices(c *gin.Context) {
+	userID := middleware.GetUserID(c)
+	uuid := c.Param("uuid")
+
+	config, err := h.configService.RefreshPrices(uuid, userID)
+	if err != nil {
+		status := http.StatusInternalServerError
+		if err == services.ErrConfigNotFound {
+			status = http.StatusNotFound
+		} else if err == services.ErrConfigForbidden {
+			status = http.StatusForbidden
+		}
+		c.JSON(status, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, config)
+}
+
 // func (h *ConfigurationHandler) ExportJSON(c *gin.Context) {
 // 	userID := middleware.GetUserID(c)
 // 	uuid := c.Param("uuid")