feat(web): add teams page and RBAC navigation/route gating (MS21-UI-005, RBAC-001, RBAC-002) (#595)

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

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

@@ -118,6 +118,23 @@ describe("UsersSettingsPage", () => {
     });
   });
 
+  it("shows access denied to non-admin users", async () => {
+    fetchUserWorkspacesMock.mockResolvedValueOnce([
+      {
+        id: "workspace-1",
+        name: "Personal Workspace",
+        ownerId: "owner-1",
+        role: WorkspaceMemberRole.MEMBER,
+        createdAt: "2026-01-01T00:00:00.000Z",
+      },
+    ]);
+
+    render(<UsersSettingsPage />);
+
+    expect(await screen.findByText("Access Denied")).toBeInTheDocument();
+    expect(fetchAdminUsersMock).not.toHaveBeenCalled();
+  });
+
   it("invites a user with email and role from the dialog", async () => {
     const user = userEvent.setup();
     render(<UsersSettingsPage />);