Update Self destructing messages

Self-destructing-messages.md

@@ -71,6 +71,22 @@ Preconditions:
 
 **#1833 Delete messages when their self-destruct timers expire**
 
+#1836 Automatically decline incoming private group invitations when they self-destruct
+
+**MR 1389 Automatically decline incoming private group invitations when they self-destruct**
+ 
+Test instructions:
+
+* use two or more contacts
+* create various private groups
+* invite contacts to private groups
+* accept/decline invitations
+* enable/disable disappearing messages throughout the process
+* ensure that messages sent with enabled timers self-destruct (also while private conversation is open)
+* ensure that open invitations get automatically declined and are recognizable as automatic for the *sender* of the decline
+
+**#1833 Delete messages when their self-destruct timers expire**
+
 Create a component that tracks pending self-destruct timers and deletes messages when their self-destruct timers expire.
 
 Conversation clients will register messages for deletion during delivery. The new component will be responsible for calling back into the client when a message is due to be deleted. This will allow the client to take any necessary steps before deletion, such as declining an open introduction.
@@ -95,6 +111,25 @@ To test this scenario:
 - [ ] device2 sends device1 a message.  
 - [ ] device1 receives message, together with the automatically generated messages informing them that the message they just received is not going to be seld-destucted.
 
+**MR1382 Delete messages when their self-destruct timers expire (no UI) **
+
+This branch implements automatic deletion of private messages and attachments. The sender starts the timer for a private message when it's acked; the recipient starts the timer when the private message is read.
+
+When an attachment is received, we check whether it's listed as an attachment by any private message received in the conversation so far. If not, an orphan cleanup timer with a duration of 28 days is started. The timer is stopped if we receive a private message that lists the attachment; otherwise the orphaned attachment is deleted.
+
+Manual deletion of private messages with missing attachments is now allowed; the orphan cleanup timer will ensure any attachments that arrive after their private messages have been deleted will eventually be deleted too. Making this change was easier than updating the attachment format to indicate whether each attachment belongs to a private message with a self-destruct timer, and I think it improves the manual deletion feature.
+
+This branch also contains an unrelated change: moving ConversationManagerImpl to the conversation package (like its interface). I can move this change to a separate MR if preferred.
+
+The default timer duration is changed to 1 minute for easier testing; we should revert this before merging the feature branch.
+
+Part of #1833.
+
+Was WIP because the UI isn't updated when messages are deleted. @grote let's discuss whether to merge this to the feature branch and add the UI changes separately, or add them before merging this MR. We also need to update the onboarding text to explain that the recipient's timer starts when the message is read.
+
+**#1819 Crash if screen is rotated during setup and "Create Account" is tapped twice**
+
+I got the following crash on the Nokia 3.1 (Android 10) while trying to reproduce another bug. During setup, I rotated the screen to landscape and back to portrait after tapping "Create Account", which caused the progress wheel to disappear and the "Create Account" button to reappear. I tapped the button again and Briar crashed: