kern/59544: Add support for 256 colours to wscons

[kolipe.c%exoticsilicon.com@localhost]

>Number:         59544
>Category:       kern
>Synopsis:       Add support for 256 colours to wscons
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 22 12:45:00 +0000 2025
>Originator:     Crystal Kolipe
>Release:        10.1-release
>Organization:
Exotic Silicon
>Environment:
>Description:
The framebuffer console only supports direct selection of eight colours, with another eight being indirectly selectable using the highlight/bold attribute.

In the case of 32-bit rasops displays, the underlying hardware supports much more.  As a first step, add support for direct selection of the bright colours for both foreground and background, as well as separately increasing the colour palette to 256.
>How-To-Repeat:

>Fix:
I posted a patch to the tech-kern mailing list to implement these two features:

https://mail-index.netbsd.org/tech-kern/2025/07/06/msg030599.html