Clear refresh token cookie during logout to enforce full session termination

Co-Authored-By: Codex <codex@openai.com>

tests/stores/login.test.js

@@ -163,6 +163,12 @@ describe("loginStore", () => {
       expect(store.isLoggedIn).toBe(false);
       expect(store.$router.push).toHaveBeenCalledWith("/login");
     });
+
+    it("clears refresh token cookie on logout", () => {
+      document.cookie = "luciaRefreshToken=refresh-token";
+      store.logOut();
+      expect(document.cookie).not.toContain("luciaRefreshToken=");
+    });
   });
 
   describe("getUserData", () => {