work-for-factions: never take player focus (always work in background)

[jiransj]

Summary

Makes the work script never steal player focus:

• \shouldFocus\ is now always \alse, so faction/company work, studying and crimes are always performed in the background (even at the cost of the 20% non-focus penalty).
• The crime code path also defaults to non-focused when running as an imported function.
• Existing --no-focus\ / --no-tail-windows\ options remain available for compatibility.

Motivation

The work-for-factions script was taking player focus, blocking other activities. This forces all its work to be backgrounded.