cmd-A in interactive shell should only select text in current prompt

As you can see in the recording below when pressing cmd+a (ctrl+a) in the interactive command prompt all the text in the interactive window gets selected.

Suggestions: it would be convenient if only the text in the currently interactive prompt (only (foo bar 5) would get selected.

Actually the cursor behavior in the interactive window is a bit confusing as you can move th cursor outside the editable line and it's still blinking (suggesting that the text can be edited when in fact it's read only).

Suggestion:

• Limit the cursor movement to the editable prompt
• if the cursor is in the first or last line of the interactive prompt arrow up/down should cycle through previous read commands
• escape key could toggle read-only mode of the interactive window allowing the cursor to move everywhere but disabling the prompt (in read-only cmd+a could select all the text)
• when not in read-only mode clicking anywhere in the interactive window should force the cursor somewhere into the editble region of the prompt (currently when clicking right after the > in the prompt one can not enter any text)

Start with the interactive command prompt and editable-line/cursor behavior described in the issue, using the linked recording to reproduce cmd/ctrl-A and cursor movement. Review the prompt's handling of selection, clicks, arrow keys, and Escape, then verify that editing is confined to the current prompt while read-only selection still behaves as described.