Feature Request: Get or apply Email Signatures

Is your feature request related to a problem? Please describe the problem.

At the moment, there is no API to obtain the (default) email signatures, so the user is forced to open a draft and add it manually.

Describe the solution you'd like.

We need access to the mailbox or user settings in order to retrieve all email signatures, so that new emails can be created with the corresponding signatures.

user.getMailboxSettings().getSignatures()

Additional context?

No response

該 issue 提議使用 user.getMailboxSettings().getSignatures()，但沒有指出任何 repository 檔案、測試或現有入口點。首先定位 Java SDK 中對 mailbox-settings 的支援，並確認底層 Microsoft Graph 能力；完成標準是 SDK 能夠取得所有電子郵件簽名，並具有測試覆蓋率。