24-hour military time entry

Is your feature request related to a problem? Please describe.

I would like if the calendar would accept military-style time entry (e.g. 1300 -> 1:00 PM / 13:00, or 1747 -> 5:47 PM / 17:47) instead of simply ignoring such input. This significantly speeds up time entry (especially using numpad), and this functionality is present in many other calendars (including Google Calendar and Outlook, to name a few) and many other software applications.

Describe the solution you'd like

I'd like if entering four digits in a row is read as 24-hour time and converted appropriately.

Describe alternatives you've considered

The alternative is the current state, which is that such entry is simply ignored and reverted when leaving the textbox.

Additional context

The specification is described in Chapter 3, paragraphs 326–328 of the October 2010 CCEB ACP 121(I).

Start by locating the calendar's time-entry field and the validation or conversion logic that currently rejects four-digit input. Check how existing 12-hour and 24-hour values are handled, then verify that inputs such as 1300 and 1747 are accepted and converted to the corresponding displayed times without regressing current entry behavior.