DESIGN: new mail notification redesign request

[User-green]

Goal

A starting point for discussing a redesign of the new-mail notification on Android, to make it a bit more useful and actionable while staying true to Aster's privacy-first posture. Nothing here is fixed; these are suggestions to react to.

Current state

app/src/main/kotlin/org/astermail/android/notifications/MailPollingWorker.kt (post_new_mail):

• Title = sender, text = subject (single line).
• Expanded uses InboxStyle with two lines (subject + preview).
• Group summary for multiple messages.
• A "private notifications" mode shows only sender + "New message" with VISIBILITY_SECRET.
• No avatar/large icon, no quick actions, no attachment indicator, no MessagingStyle.

Reference (Gmail for Android, 2025)

For comparison, not as a target to copy:

• Collapsed: sender, subject (with a paperclip indicator when an attachment is present), one-line body snippet, and a sender avatar on the right that becomes an image thumbnail when the attachment is a photo.
• Expanded: a larger preview; photo attachments shown prominently, non-image files shown as pills (type + filename). Note: previews replace the body text.
• Quick actions: Mark as read (shown first), Reply, and Archive or Delete.

Ideas worth considering

Roughly in order of value-to-effort, for discussion:

• Quick actions such as Mark as read and Archive/Delete (and maybe Reply). These add little privacy cost since they reveal no extra content.
• A sender avatar / large icon, with the app icon as fallback.
• A subtle attachment indicator (presence only, no content).
• MessagingStyle for a cleaner sender/snippet layout and grouping.
• Optionally, richer previews (image thumbnails, file pills) - but likely best kept opt-in (see below).

Privacy notes

Since Aster is privacy-first (it blocks remote images in mail and already has a secret-content notification mode), it might be worth being careful about how much a notification reveals. Body snippets, attachment thumbnails, and file names can surface on the lock screen and notification shade, and may sync to paired devices. A few things that could help:

• Defaulting previews/snippets to a more private level, with richer detail as an opt-in.
• Keeping notification rendering on-device (the polling worker already builds them locally).
• Respecting lock-screen sensitivity (hide details when locked, show when unlocked).

Possible setting: notification detail level

One option could be a single "Notification privacy" setting with escalating levels, for example:

1. Hide all details - generic "New message".
2. Sender only.
3. Sender + subject (a reasonable default candidate).
4. Sender + subject + one-line preview.
5. Full - preview plus attachment thumbnails / file pills.

Possibly paired with a "Hide details on lock screen" toggle. The existing private-notifications mode would map naturally onto the lower levels.

Open questions

• Inline reply (RemoteInput) and how it would interact with compose/encryption.
• Where an attachment indicator fits in the Aster design language (defer to design).
• Whether per-account or per-folder notification levels are desired.

Happy to iterate on any of this - treat it as a conversation starter rather than a spec.

[findleyl]

Yes, go ahead.