GHSA-q84f-53jg-9ppm - better-auth: Device login approval does not show the requesting client or permissions

## Am I affected? You may be affected if you use `better-auth` from `1.3.8-beta.3` up to, but not including, `1.7.0-rc.3`, and you enable the `deviceAuthorization()` plugin. This range includes all 1.6 releases. You are affected only if all of these are also true: - An attacker can start a device request: `validateClient` is not configured, or the attacker can use a valid public client. - Before allowing approval, your approval page does not show, from server-checked data, which client is asking and the exact permissions it requests. - Users may approve a code or complete verification link they did not start and cannot compare with a device they have. - Your application accepts the session token that the device flow returns, for example through the bearer plugin. You are not affected if you do not enable the opt-in `deviceAuthorization()` plugin. ## Summary The device authorization plugin lets a user sign in on one device by approving a short code on another. In affected versions, the approval information given to the user leaves out which client asked for access and which permissions it wants. The official approval examples therefore show only a generic request and a code, so users cannot tell their own device from an attacker's request. ## Impact An attacker who convinces a signed-in user to approve the attacker's code receives a live Better Auth session token for that user. The attacker can then read or change any data the user's account can access. The attack needs the opt-in device flow, a request the attacker creates, and a user who actively approves it; it is not a sign-in bypass without user action. ## Patches The fix first shipped in `1.7.0-rc.3`. Upgrade to `better-auth@1.7.0` or later. No 1.6 release contains the fix. After upgrading, `GET /device` returns the requesting `client_id` and `scope` to the signed-in account that owns the request. If you built your own approval page, update it to show that client and those permissions, and keep appro