Add ghost role raffles (#26629)

* Add ghost role raffles

* GRR: Fix dialogue sizing, fix merge

* GRR: Add raffle deciders (winner picker)

* GRR: Make settings prototype based with option to override

* GRR: Use Raffles folder and namespace

* GRR: DataFieldify and TimeSpanify

* GRR: Don't actually DataFieldify HashSet<ICommonSession>s

* GRR: add GetGhostRoleCount() + docs

* update engine on branch

* Ghost role raffles: docs, fix window size, cleanup, etc

* GRR: Admin UI

* GRR: Admin UI: Display initial/max/ext of selected raffle settings proto

* GRR: Make a ton of roles raffled

Content.Server/Ghost/Roles/Raffles/IGhostRoleRaffleDecider.cs

@@ -0,0 +1,28 @@
+using Robust.Shared.Player;
+
+namespace Content.Server.Ghost.Roles.Raffles;
+
+/// <summary>
+/// Chooses a winner of a ghost role raffle.
+/// </summary>
+[ImplicitDataDefinitionForInheritors]
+public partial interface IGhostRoleRaffleDecider
+{
+    /// <summary>
+    /// Chooses a winner of a ghost role raffle draw from the given pool of candidates.
+    /// </summary>
+    /// <param name="candidates">The players in the session at the time of drawing.</param>
+    /// <param name="tryTakeover">
+    /// Call this with the chosen winner as argument.
+    /// <ul><li>If <c>true</c> is returned, your winner was able to take over the ghost role, and the drawing is complete.
+    /// <b>Do not call <see cref="tryTakeover"/> again after true is returned.</b></li>
+    /// <li>If <c>false</c> is returned, your winner was not able to take over the ghost role,
+    /// and you must choose another winner, and call <see cref="tryTakeover"/> with the new winner as argument.</li>
+    /// </ul>
+    ///
+    /// If <see cref="tryTakeover"/> is not called, or only returns false, the raffle will end without a winner.
+    /// Do not call <see cref="tryTakeover"/> with the same player several times.
+    /// </param>
+    void PickWinner(IEnumerable<ICommonSession> candidates, Func<ICommonSession, bool> tryTakeover);
+}
+