Research the PAL transparency handling mechanism (and document all verifiable results)

[rdw-software]

The original article mentions how transparency is handled in color palettes. Unfortunately, it doesn't include any sources.

IIRC, the information was provided by curiosity in one of the forums, but I don't have the link right now.

TODOs:

• [ ] Find the original source/forum post and link it as a (hopefully credible) source
• [ ] Programmatically verify that all palettes (and SPRs, i.e., default palettes) include no alpha value
• [ ] If any do, verify that the alpha value stored in the color palette is indeed unused
• [ ] Additionally, verify that any palette using these "near-transparent" colors actually needs them to be fully transparent

Basically, some due diligence before the information is included in the docs. Since the old repo still exists, there's no urgency.