Limit decimal precision depending on the circumstances

It should always be possible to know the order of magnitude of a given result at a glance. Currently with large numbers, this isn't possible. Steps to reproduce: Multiply 2 random large numbers.

In this example the calculator should show E26 at the right side and only show as many decimal places as can be shown on the screen without the need to scroll to the right.

Start by reproducing the large-number multiplication described in the issue on the Android calculator. Trace the result display and formatting behavior, then verify that the magnitude indicator remains visible and that decimal places fit on screen without horizontal scrolling.

Written by the indexing model from the issue text.