Feature: Display single-line diagnostic on Ctrl-C interruption of a flow

When a user interrupts a flow using Ctrl-C, provide a single-line diagnostic view with the Conversation ID that was interrupted, the start/end time of the conversation, such that users can paste this into bug reports for investigations.

The info should be low contrast/grey, as it is not "priority" information, but just used for any feedback.

If the /issue command is used immediately after the Ctrl-C, provide this context automatically.