Sneak preview of the "filled border" functionality:
This is still only a 99% solution - there are tiny gaps when using "candy style" borders near sector boundaries, where a few pixels inside the border might not be filled. Only noticeable if you go looking, and fixing that would be extremely computationally expensive, so I probably won't bother. Other minor issues include overlapping polities such as the Vegan Autonomous District (Spinward Marches), Ral Ranta (Hinterworlds), and the sub-polities of the Julian Protectorate - the translucent backgrounds blend. Also, world names (and the worlds themselves) have a black background - I may try and fix that.
This will be controlled by an option/parameter, but I haven't hooked that up yet.
One issue is that this makes the polities without micro-scale borders - namely, the Hive Federation and Two Thousand Worlds - more glaringly incomplete. I could toss in "make this entire sector purple/green" placeholders like I did for Stiatlchepr. Opinions?