Put friends on the same team (#3994)

Fixes #3911

## Description:

- Server captures `publicId` and `friends` from `getUserMe()` and
includes each player's in-game friend `clientID`s in `PlayerSchema` on
game start
- Team assignment treats friends as a **soft preference** (best-effort):
a non-clan player goes to the team where the most of their friends
already are; if that team is full they spill to the next-emptiest team
rather than getting kicked
- Clans remain strict (kick overflow) since clan membership is an
explicit opt-in; friends are implicit, so a friend-of-friend chain that
doesn't fit shouldn't bench anyone
- Friendship is symmetric — an edge from either direction counts, which
keeps things working when one side's `getUserMe` is stale
- Lobby preview unchanged — friend grouping only takes effect once the
game actually starts (avoids exposing friend lists in the lobby payload)


## 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

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

evan

src/server/Client.ts

@@ -21,5 +21,7 @@ export class Client {
     public clanTag: string | null,
     public ws: WebSocket,
     public readonly cosmetics: PlayerCosmetics | undefined,
+    public readonly publicId: string | undefined,
+    public readonly friends: string[],
   ) {}
 }