feat: improve mail thread and send mail

[krantheman]

MailboxView

• Fix sockets
• Add Empty mailbox for junk and trash

Mail Thread

• Add quick mail editor for drafts

Screen.Recording.2025-08-29.at.5.21.17.PM.mov

Compose Mail

• Commonify ComposeMailEditor so that it can be used outside the dialog as well
• Toggle between reply, reply to, and forward before draft is created in backend
• Add forwarded header for forwarded messages
• Focus on 'To' field while forwarding
• Fix issue where attachments were not being forwarded
• Make quoted content toggleable in editor
• Add auto save (debounced at 2 seconds)
• Add toasts for saving draft, sending mails, and errors
• Handle height dynamically placing attachments and quoted button below

PWA

• Make toolbar stick to keyboard
• Rearrange layout to move send and discard button on top

video_2025-08-29_17-38-50.mp4

Want to make more changes in PWA but didn't want to further bloat this PR.

Closes: #258; Closes: #256; Closes: #251; Closes: #247