feat: add support for ! history and readline command in roundup-admin Ad support to change input mode emacs/vi using new 'readline' roundup-admin command. Also bind keys to command/input strings, List numbered history and allow rerunning a command with !<number> or allow user to edit it using !<number>:p. admin_guide.txt: Added docs. admin.py: add functionality. Reconcile import commands to standard. Replace IOError with FileNotFoundError no that we have removed python 2.7 support. Add support for identifying backend used to supply line editing/history functions. Add support for saving commands sent on stdin to history to allow preloading of history. test_admin.py: Test code. Can't test mode changes as lack of pty when driving command line turns off line editing in readline/pyreadline3. Similarly can't test key bindings/settings. Some refactoring of test conditions that had to change because of additional output reporting backend library.

--- a/CHANGES.txt	Thu Aug 28 12:39:38 2025 -0400
+++ b/CHANGES.txt	Sun Aug 31 16:54:17 2025 -0400
@@ -36,6 +36,9 @@
   style configs will still be supported. (John Rouillard)
 - add 'q' as alias for quit in roundup-admin interactive mode. (John
   Rouillard)
+- add readline command to roundup-admin to list history, control input
+  mode etc. Also support bang (!) commands to rerun commands in history
+  or put them in the input buffer for editing. (John Rouillard)
 
 2025-07-13 2.5.0