fix alternate view perf regression (#1734)

## Description:

Have the diplomacy view only draw border, not interior tiles. Drawing
the interior tiles is a very expensive operation and caused main thread
cpu usage to spike to close to 100%.

Also change the color scheme so that neutral players are gray, and
embargoed players are red. I think long term embargo should be more of a
war state.

Added embargo update and cleaned it up to use Player instead of
PlayerID. There's no reason to pass ids around.


<img width="493" height="466" alt="Screenshot 2025-08-07 at 6 25 55 PM"
src="https://github.com/user-attachments/assets/75552036-42f1-4103-9537-234ff1c0464f"
/>

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I have read and accepted the CLA agreement (only required once).

## Please put your Discord username so you can be contacted if a bug or
regression is found:

evan

src/core/configuration/Config.ts

@@ -185,6 +185,7 @@ export interface Theme {
   // unit color for alternate view
   selfColor(): Colord;
   allyColor(): Colord;
+  neutralColor(): Colord;
   enemyColor(): Colord;
   spawnHighlightColor(): Colord;
 }