feat(auth): support browser login for managed ChatGPT accounts (#8288)

Some managed ChatGPT workspaces disable device-code authentication, so those accounts could not be added to CC Switch. Add browser login (authorization code + PKCE with a loopback callback on port 1455) to the Auth Center and the Codex provider form, including reauthentication; device-code login stays available in a method selector.

Fixes #8284

tests/components/CodexOAuthSection.test.tsx

@@ -324,6 +324,52 @@ describe("CodexOAuthSection", () => {
     expect(add).toHaveAttribute("aria-describedby", "auth-pending-chatgpt");
   });
 
+  it("reopens browser login without showing device-code controls", async () => {
+    const { settingsApi } = await import("@/lib/api");
+    const openExternal = vi
+      .spyOn(settingsApi, "openExternal")
+      .mockResolvedValue();
+    const authResult = mocks.useCodexOauth();
+    mocks.useCodexOauth.mockReturnValue({
+      ...authResult,
+      pollingState: "polling",
+      isPolling: true,
+      isAddingAccount: true,
+      deviceCode: {
+        provider: "codex_oauth",
+        device_code: "browser:flow",
+        user_code: "",
+        verification_uri:
+          "https://auth.openai.com/oauth/authorize?state=fixture",
+        expires_in: 900,
+        interval: 1,
+      },
+    });
+    try {
+      render(<CodexOAuthSection />);
+      expect(
+        screen.getByText(/已在浏览器打开 ChatGPT 的登录页/),
+      ).toBeInTheDocument();
+      expect(
+        screen.queryByText("在浏览器中输入验证码："),
+      ).not.toBeInTheDocument();
+      expect(
+        screen.queryByRole("button", { name: "复制验证码" }),
+      ).not.toBeInTheDocument();
+      expect(
+        screen.getAllByRole("button", { name: "重新打开登录页" }),
+      ).toHaveLength(1);
+      await userEvent.click(
+        screen.getByRole("button", { name: "重新打开登录页" }),
+      );
+      expect(openExternal).toHaveBeenCalledWith(
+        "https://auth.openai.com/oauth/authorize?state=fixture",
+      );
+    } finally {
+      openExternal.mockRestore();
+    }
+  });
+
   it("selects a specific account when multiple accounts are managed", async () => {
     const user = userEvent.setup();
     const onAccountSelect = vi.fn();