Feature/colorblind mode (#4150)

**Add approved & assigned issue number here:**

Resolves #2549

## Description:

Adds colorblind mode. Similar to dark mode, it exists as a toggle in
settings. When enabled, it swaps the game's theme (which is refactored
to extend from a theme base class) to use more colorblind-friendly
colors and brightness variations. Borders are darkened, and terrarin is
separated by lightness. Friendly/Foe colors and switched to blue/orange
instead of red/green.

The theme refactor supports adding new themes without having to
reimplement the color distribution system. New themes can extend the
BaseTheme and supply the data, such as palettes, team-color variations,
and terrain.

New setting:
<img width="880" height="273" alt="Screenshot 2026-06-04 at 11 30 27 AM"
src="https://github.com/user-attachments/assets/d5d573d5-cc64-4ac1-95c2-00627faf17cc"
/>

New color palette:
<img width="1119" height="757" alt="Screenshot 2026-06-04 at 11 30
59 AM"
src="https://github.com/user-attachments/assets/2bb15bc9-992b-41ae-ab0e-b01fe0c3c6bb"
/>

## 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

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

jetaviz

src/client/view/GameView.ts

@@ -872,6 +872,17 @@ export class GameView implements GameMap {
     return Array.from(this._players.values());
   }
 
+  /**
+   * Recompute every player's theme-derived colors. Call when the active theme
+   * changes mid-game (e.g. toggling colorblind mode) so existing territories
+   * re-color; the renderer palette must be refreshed afterwards.
+   */
+  refreshPlayerColors(): void {
+    for (const p of this._players.values()) {
+      p.refreshColors();
+    }
+  }
+
   playerBySmallID(id: number): PlayerView | TerraNullius {
     if (id === 0) {
       return new TerraNulliusImpl();