Refactor site building workflow and context handling; update API response structure for improved clarity and consistency. Adjust frontend components to align with new data structure, including error handling and loading states.

frontend/src/pages/Sites/List.tsx

@@ -15,6 +15,7 @@ import FormModal, { FormField } from '../../components/common/FormModal';
 import Alert from '../../components/ui/alert/Alert';
 import Switch from '../../components/form/switch/Switch';
 import ViewToggle from '../../components/common/ViewToggle';
+import ModuleNavigationTabs from '../../components/navigation/ModuleNavigationTabs';
 import { 
   PlusIcon, 
   PencilIcon, 
@@ -108,9 +109,13 @@ export default function SiteList() {
       }
     } catch (error: any) {
       // 404 means preferences don't exist yet - that's fine
-      if (error.status !== 404) {
-        console.warn('Failed to load user preferences:', error);
+      // 500 and other errors should be handled silently - user can still use the page
+      if (error?.status === 404) {
+        // Preferences don't exist yet - this is expected for new users
+        return;
       }
+      // Silently handle other errors (500, network errors, etc.) - don't spam console
+      // User can still use the page without preferences
     }
   };
 
@@ -166,10 +171,9 @@ export default function SiteList() {
           allIndustries = allIndustries.filter(i => i.slug === preferences.selectedIndustry);
         }
       } catch (error: any) {
-        // 404 means preferences don't exist yet - show all industries
-        if (error.status !== 404) {
-          console.warn('Failed to load user preferences for filtering:', error);
-        }
+        // 404 means preferences don't exist yet - show all industries (expected for new users)
+        // 500 and other errors - show all industries (graceful degradation)
+        // Silently handle errors - user can still use the page
       }
       
       setIndustries(allIndustries);
@@ -678,6 +682,13 @@ export default function SiteList() {
     );
   }
 
+  // Navigation tabs for Sites module
+  const sitesTabs = [
+    { label: 'All Sites', path: '/sites', icon: <TableIcon className="w-4 h-4" /> },
+    { label: 'Create Site', path: '/sites/builder', icon: <PlusIcon className="w-4 h-4" /> },
+    { label: 'Blueprints', path: '/sites/blueprints', icon: <FileIcon className="w-4 h-4" /> },
+  ];
+
   return (
     <div className="p-6">
       <PageMeta title="Sites Management - IGNY8" />
@@ -687,6 +698,9 @@ export default function SiteList() {
         hideSiteSector={true}
       />
       
+      {/* In-page navigation tabs */}
+      <ModuleNavigationTabs tabs={sitesTabs} />
+      
       {/* Info Alert */}
       <div className="mb-6">
         <Alert