feat(multi-tenancy): implement critical fixes for orphaned users and permissions

- Simplified HasTenantAccess permission logic to ensure every authenticated user has an account.
- Added fallback to system account for OpenAI settings in AI configuration.
- Allowed any authenticated user to check task progress in IntegrationSettingsViewSet.
- Created a script to identify and fix orphaned users without accounts.
- Updated error response handling in business endpoints for clarity.

frontend/src/pages/Settings/Sites.tsx

@@ -49,6 +49,7 @@ export default function Sites() {
     domain: '',
     description: '',
     is_active: true, // Default to true to match backend model default
+    industry: undefined as number | undefined, // Industry ID - required by backend
   });
 
   // Load sites and industries
@@ -145,6 +146,7 @@ export default function Sites() {
       domain: site.domain || '',
       description: site.description || '',
       is_active: site.is_active || false,
+      industry: site.industry,
     });
     setShowDetailsModal(true);
   };
@@ -177,6 +179,7 @@ export default function Sites() {
       domain: '',
       description: '',
       is_active: true, // Default to true to match backend model default
+      industry: undefined,
     });
     setShowSiteModal(true);
   };
@@ -188,6 +191,7 @@ export default function Sites() {
       domain: site.domain || '',
       description: site.description || '',
       is_active: site.is_active || false,
+      industry: site.industry,
     });
     setShowSiteModal(true);
   };
@@ -247,6 +251,7 @@ export default function Sites() {
         domain: '',
         description: '',
         is_active: false,
+        industry: undefined,
       });
       await loadSites();
     } catch (error: any) {
@@ -313,6 +318,22 @@ export default function Sites() {
       required: true,
       placeholder: 'Enter site name',
     },
+    {
+      key: 'industry',
+      label: 'Industry',
+      type: 'select',
+      value: formData.industry?.toString() || '',
+      onChange: (value: any) => setFormData({ ...formData, industry: value ? parseInt(value) : undefined }),
+      required: true,
+      placeholder: 'Select an industry',
+      options: [
+        { value: '', label: 'Select an industry...' },
+        ...industries.map(industry => ({
+          value: industry.id.toString(),
+          label: industry.name,
+        })),
+      ],
+    },
     {
       key: 'domain',
       label: 'Domain',
@@ -428,6 +449,7 @@ export default function Sites() {
               domain: '',
               description: '',
               is_active: false,
+              industry: undefined,
             });
           }}
           onSubmit={handleSaveSite}