fix(api,web): add workspace context to widgets and auto-detect workspace ID (#532)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

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

@@ -202,9 +202,13 @@ export async function apiRequest<T>(endpoint: string, options: ApiRequestOptions
       ...baseHeaders,
     };
 
-    // Add workspace ID header if provided (recommended over query string)
-    if (workspaceId) {
-      headers["X-Workspace-Id"] = workspaceId;
+    // Add workspace ID header — use explicit value, or auto-detect from localStorage
+    const resolvedWorkspaceId =
+      workspaceId ??
+      (typeof window !== "undefined" ? localStorage.getItem("mosaic-workspace-id") : null) ??
+      undefined;
+    if (resolvedWorkspaceId) {
+      headers["X-Workspace-Id"] = resolvedWorkspaceId;
     }
 
     // Add CSRF token for state-changing requests (POST, PUT, PATCH, DELETE)