Duo partner SP always same: randomize players before team assignment (#1051)

## Description:

See report here:
https://discord.com/channels/1284581928254701718/1378762423175221319

In Singleplayer Teams > Duos, your duo partner will be the same every
time. In World map for example, it will always Norway.

Fix: randomizing Nation players before their team assignment. This is
done for all Team modes in Singleplayer and Multiplayer.

Other behaviour is unchanged. Clan-players keep their own assignment
logic, and Human non-clan player assignment stays the same. The human in
singleplayer Duos mode lands in Team 1 everytime but with a different
Nation as other team member.

BEFORE
![Before SP Duos
modal](https://github.com/user-attachments/assets/78628b06-d621-4203-86ae-046e081a46fb)

![Before SP Duos always Team
1](https://github.com/user-attachments/assets/6e7ec19c-b1e5-4642-beb9-93b723a27618)

![Before SP Duos always Team 1 always Norway team
member](https://github.com/user-attachments/assets/34794d16-ce90-43ca-a5c2-9827e7c944f5)


AFTER

![After SP Duos Team 1 random duo
partner](https://github.com/user-attachments/assets/5a1d7d6a-74f2-472f-a0ff-ad94e9ae80bd)


## 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 understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

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

tryout33

src/core/game/TeamAssignment.ts

@@ -1,4 +1,6 @@
-import { PlayerInfo, Team } from "./Game";
+import { PseudoRandom } from "../PseudoRandom";
+import { simpleHash } from "../Util";
+import { PlayerInfo, PlayerType, Team } from "./Game";
 
 export function assignTeams(
   players: PlayerInfo[],
@@ -56,7 +58,19 @@ export function assignTeams(
   }
 
   // Then, assign non-clan players to balance teams
-  for (const player of noClanPlayers) {
+  let nationPlayers = noClanPlayers.filter(
+    (player) => player.playerType === PlayerType.FakeHuman,
+  );
+  if (nationPlayers.length > 0) {
+    // Shuffle only nations to randomize their team assignment
+    const random = new PseudoRandom(simpleHash(nationPlayers[0].id));
+    nationPlayers = random.shuffleArray(nationPlayers);
+  }
+  const otherPlayers = noClanPlayers.filter(
+    (player) => player.playerType !== PlayerType.FakeHuman,
+  );
+
+  for (const player of otherPlayers.concat(nationPlayers)) {
     let team: Team | null = null;
     let teamSize = 0;
     for (const t of teams) {