refactor: redesign planos interface with design system patterns

- Create CreatePlanModal component with Headless UI Dialog
- Implement dark mode support throughout plans UI
- Update plans/page.tsx with professional card layout
- Update plans/[id]/page.tsx with consistent styling
- Add proper spacing, typography, and color consistency
- Implement smooth animations and transitions
- Add success/error message feedback
- Improve form UX with better input styling

backend/internal/api/handlers/tenant.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"encoding/json"
+	"log"
 	"net/http"
 
 	"aggios-app/backend/internal/domain"
@@ -100,6 +101,8 @@ func (h *TenantHandler) GetPublicConfig(w http.ResponseWriter, r *http.Request)
 		"logo_horizontal_url": tenant.LogoHorizontalURL,
 	}
 
+	log.Printf("📤 Returning tenant config for %s: logo_url=%s", subdomain, tenant.LogoURL)
+
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	json.NewEncoder(w).Encode(response)
 }