fix: refresh tokens in approve command when unauthorized

[pullfrog]

Fixes #460.

What changed

• approve now handles Unauthorized from list_auth_sessions by re-running login, which refreshes tokens when possible.
• After re-login, it retries listing auth sessions once.
• When no sessions are pending, the command now continues to the next account instead of returning early from the entire command.

Validation

• cargo test -p steamguard-cli --bin steamguard

  ^{｜ View workflow run ｜ Triggered by Pullfrog ｜ Using GPT Codex ｜ 𝕏}