fix(web): address review findings — workspace ID threading and error handling

- Thread workspaceId into fetchDomains() so X-Workspace-Id header is sent
- Guard useEffect against null workspaceId with early return; add workspaceId to dep array
- Add catch block in handleCreate to surface errors via setError
- Remove console.log from handleEdit

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/app/(authenticated)/settings/domains/page.tsx

@@ -367,13 +367,17 @@ export default function DomainsPage(): ReactElement {
   const [isCreating, setIsCreating] = useState(false);
 
   useEffect(() => {
+    if (!workspaceId) {
+      setIsLoading(false);
+      return;
+    }
     void loadDomains();
-  }, []); // loadDomains is defined in this scope and stable
+  }, [workspaceId]);
 
   async function loadDomains(): Promise<void> {
     try {
       setIsLoading(true);
-      const response = await fetchDomains();
+      const response = await fetchDomains(undefined, workspaceId ?? undefined);
       setDomains(response.data);
       setError(null);
     } catch (err) {
@@ -383,9 +387,8 @@ export default function DomainsPage(): ReactElement {
     }
   }
 
-  function handleEdit(domain: Domain): void {
+  function handleEdit(_domain: Domain): void {
     // TODO: Open edit modal/form
-    console.log("Edit domain:", domain);
   }
 
   async function handleDelete(domain: Domain): Promise<void> {
@@ -407,6 +410,8 @@ export default function DomainsPage(): ReactElement {
       await createDomain(data, workspaceId ?? undefined);
       setCreateOpen(false);
       await loadDomains();
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to create domain.");
     } finally {
       setIsCreating(false);
     }

apps/web/src/lib/api/domains.ts

@@ -44,7 +44,10 @@ export interface DomainFilters {
 /**
  * Fetch all domains
  */
-export async function fetchDomains(filters?: DomainFilters): Promise<ApiResponse<Domain[]>> {
+export async function fetchDomains(
+  filters?: DomainFilters,
+  workspaceId?: string
+): Promise<ApiResponse<Domain[]>> {
   const params = new URLSearchParams();
 
   if (filters?.search) {
@@ -60,7 +63,7 @@ export async function fetchDomains(filters?: DomainFilters): Promise<ApiResponse
   const queryString = params.toString();
   const endpoint = queryString ? `/api/domains?${queryString}` : "/api/domains";
 
-  return apiGet<ApiResponse<Domain[]>>(endpoint);
+  return apiGet<ApiResponse<Domain[]>>(endpoint, workspaceId);
 }
 
 /**