Feature Request: Built-in Account Deletion Confirmation Email & Grace Period

### 🔖 Enhancement description

Add a built-in account deletion confirmation flow with a secure, expiring, one-time confirmation link.

When a user requests account deletion, Appwrite could send a predefined account-deletion confirmation email, similar to existing authentication emails. After confirmation, the account could enter a `pending deletion` state and remain disabled/recoverable for a configurable grace period (e.g. 7 days) before permanent deletion.

This would avoid requiring developers to implement their own deletion tokens, confirmation emails, soft-delete logic, and scheduled permanent deletion.

### 🎤 Pitch

Account deletion is one of the most destructive actions an application can perform, yet developers currently need to build the confirmation and delayed-deletion flow themselves.

A built-in solution would give Appwrite developers a secure and standardized way to handle this: confirm the deletion by email, temporarily disable the account, provide a configurable grace period, and permanently delete it afterward.

This would make account deletion safer for users and significantly reduce the amount of security-sensitive custom logic developers need to implement.

### 👀 Have you spent some time to check if this issue has been raised before?

- [x] I checked and didn't find similar issue

### 🏢 Have you read the Code of Conduct?

- [x] I have read the [Code of Conduct](https://github.com/appwrite/.github/blob/main/CODE_OF_CONDUCT.md)

The request does not name files, tests, or entry points. Start by locating Appwrite's existing authentication email flow and account-deletion handling; done means the confirmation, pending-deletion, grace-period, recovery, and permanent-deletion lifecycle is defined and covered by tests.

Written by the indexing model from the issue text.