fix: fix online mode after offline-first architecture changes

- Fix nil pointer dereference in PricingHandler alert methods
- Add automatic MariaDB connection on startup if settings exist
- Update setupRouter to accept mariaDB as parameter
- Fix offline mode checks: use h.db instead of h.alertService
- Update setup handler to show restart required message
- Add warning status support in setup.html UI

This ensures that after saving connection settings, the application
works correctly in online mode after restart. All repositories are
properly initialized with MariaDB connection on startup.

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

internal/handlers/pricing.go

@@ -639,6 +639,18 @@ func (h *PricingHandler) RecalculateAll(c *gin.Context) {
 }
 
 func (h *PricingHandler) ListAlerts(c *gin.Context) {
+	// Check if we're in offline mode
+	if h.db == nil {
+		c.JSON(http.StatusOK, gin.H{
+			"alerts":   []interface{}{},
+			"total":    0,
+			"page":     1,
+			"per_page": 20,
+			"offline":  true,
+		})
+		return
+	}
+
 	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
 	perPage, _ := strconv.Atoi(c.DefaultQuery("per_page", "20"))
 
@@ -664,6 +676,15 @@ func (h *PricingHandler) ListAlerts(c *gin.Context) {
 }
 
 func (h *PricingHandler) AcknowledgeAlert(c *gin.Context) {
+	// Check if we're in offline mode
+	if h.db == nil {
+		c.JSON(http.StatusServiceUnavailable, gin.H{
+			"error":   "Управление алертами доступно только в онлайн режиме",
+			"offline": true,
+		})
+		return
+	}
+
 	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
 	if err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid alert id"})
@@ -679,6 +700,15 @@ func (h *PricingHandler) AcknowledgeAlert(c *gin.Context) {
 }
 
 func (h *PricingHandler) ResolveAlert(c *gin.Context) {
+	// Check if we're in offline mode
+	if h.db == nil {
+		c.JSON(http.StatusServiceUnavailable, gin.H{
+			"error":   "Управление алертами доступно только в онлайн режиме",
+			"offline": true,
+		})
+		return
+	}
+
 	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
 	if err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid alert id"})
@@ -694,6 +724,15 @@ func (h *PricingHandler) ResolveAlert(c *gin.Context) {
 }
 
 func (h *PricingHandler) IgnoreAlert(c *gin.Context) {
+	// Check if we're in offline mode
+	if h.db == nil {
+		c.JSON(http.StatusServiceUnavailable, gin.H{
+			"error":   "Управление алертами доступно только в онлайн режиме",
+			"offline": true,
+		})
+		return
+	}
+
 	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
 	if err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid alert id"})