Mailbox system optimisation

Optimise the existing mailbox system to improve user experience. Including but not limited to enriching email content formatting options, optimising the paging function of mailbox interface, etc.

• Enrich email content formatting options: Add more email formatting options, such as fonts, colours, lists, quote blocks, etc., to enhance the flexibility of users in composing emails. Support embedding pictures, links and attachments for more convenient operation.
• Optimise the paging function of mailbox interface: implement the paging display of mail list and allow users to customize the number of emails displayed on each page.
• Optimise paging navigation, so that users can quickly locate and jump to specific pages. Other optimisations:Improve the loading speed of mailboxes to ensure the smooth operation of mass emails. Add more rich filtering and sorting options in the interface, which is convenient for users to manage emails.

Expected Result: Users can experience a more intuitive and efficient mailbox experience, including richer email composing functions and optimised paging interface.