fix: defer no-wait auth polling hint

[hehanlin1996]

Summary

Clarifies the auth login --no-wait --json hint for AI agents so they deliver the verification URL before starting the blocking device-code polling step.
This keeps the existing opaque URL warning while avoiding same-turn polling before the user has received the URL.

Changes

• Update the no-wait JSON hint to relay verification_url first and resume polling only after delivery, such as in the background or next turn.
• Add a regression test for the no-wait JSON hint flow.

Test Plan

• Unit tests pass: go test ./cmd/auth -count=1
• Manual local verification confirms the lark xxx command works as expected: N/A, scoped hint-text change covered by cmd/auth unit tests.

Related Issues

• Feedback C1/Device-flow auth login guidance makes AI agents block the turn, causing silent hangs on non-streaming harnesses larksuite/cli#928