feat(CS-P3): throne registration via Sinior/Crown talk (223/216) after defenses down + both switches held; reachable defense positions

src/GameLogic/CastleSiege/CastleSiegeContext.cs

@@ -169,26 +169,38 @@ public class CastleSiegeContext
     }
 
     /// <summary>
-    /// Evaluates the throne capture: if the siege is running, all defenses are destroyed, the throne is not
-    /// yet taken, and one guild holds BOTH Crown Switches at once, that guild captures the throne.
+    /// Attempts to capture the throne for a guild (called when a member registers at the Sinior/Crown NPC).
+    /// Succeeds only during the siege when the throne is free, all castle defenses are destroyed, and the
+    /// guild is currently holding BOTH Crown Switches (a member standing on each).
     /// </summary>
-    /// <returns>The guild that just captured the throne (for announcing), or <c>null</c> if nothing changed.</returns>
-    public string? EvaluateCapture()
+    /// <param name="guildName">The capturing guild's name.</param>
+    /// <returns>Whether it succeeded and a human-readable reason/result message.</returns>
+    public (bool Success, string Reason) TryCaptureThrone(string guildName)
     {
-        if (this.Phase != CastleSiegePhase.Siege || this._occupier is not null || this._defensesRemaining > 0)
+        if (this.Phase != CastleSiegePhase.Siege)
         {
-            return null;
+            return (false, "The siege is not running.");
         }
 
-        var holder217 = this._switchHolders[217];
-        var holder218 = this._switchHolders[218];
-        if (holder217 is not null && holder217 == holder218)
+        if (this._occupier is not null)
         {
-            this._occupier = holder217;
-            return holder217;
+            return (false, this._occupier == guildName
+                ? "Your guild already holds the throne."
+                : $"The throne is already held by '{this._occupier}'.");
         }
 
-        return null;
+        if (this._defensesRemaining > 0)
+        {
+            return (false, $"Destroy the castle defenses first ({this._defensesRemaining} remaining).");
+        }
+
+        if (this._switchHolders[217] != guildName || this._switchHolders[218] != guildName)
+        {
+            return (false, "Your guild must be holding BOTH Crown Switches at once (stand a member on each).");
+        }
+
+        this._occupier = guildName;
+        return (true, "throne captured");
     }
 
     /// <summary>Returns a human-readable status summary for admin display.</summary>

src/GameLogic/CastleSiege/CastleSiegeThroneCaptureTalkPlugIn.cs

@@ -0,0 +1,83 @@
+// <copyright file="CastleSiegeThroneCaptureTalkPlugIn.cs" company="MUnique">
+// Licensed under the MIT License. See LICENSE file in the project root for full license information.
+// </copyright>
+
+namespace MUnique.OpenMU.GameLogic.CastleSiege;
+
+using System.Linq;
+using System.Runtime.InteropServices;
+using MUnique.OpenMU.GameLogic.NPC;
+using MUnique.OpenMU.GameLogic.PlugIns;
+using MUnique.OpenMU.GameLogic.PlugIns.PeriodicTasks;
+using MUnique.OpenMU.GameLogic.Views;
+using MUnique.OpenMU.Interfaces;
+using MUnique.OpenMU.PlugIns;
+
+/// <summary>
+/// Handles registering on the throne at the Sinior (223) / Crown (216) NPCs on Valley of Loren.
+/// A registered guild takes the throne only when it has destroyed all castle defenses (gates + statues)
+/// AND is holding both Crown Switches (a member standing on each). The guild on the throne when the siege
+/// ends becomes the castle owner. Capturing broadcasts a server-wide golden message.
+/// </summary>
+[Guid("CA5710A0-7A1B-4C2D-8E3F-000000000223")]
+[PlugIn]
+[Display(Name = "Castle Siege Throne (Sinior/Crown)", Description = "Registers a guild on the throne (Sinior 223 / Crown 216) once defenses are down and both switches held.")]
+public class CastleSiegeThroneCaptureTalkPlugIn : IPlayerTalkToNpcPlugIn
+{
+    private static readonly short[] ThroneNpcNumbers = { 223, 216 };
+
+    /// <inheritdoc />
+    public async ValueTask PlayerTalksToNpcAsync(Player player, NonPlayerCharacter npc, NpcTalkEventArgs eventArgs)
+    {
+        if (!ThroneNpcNumbers.Contains(npc.Definition.Number))
+        {
+            return;
+        }
+
+        eventArgs.HasBeenHandled = true;
+
+        var context = CastleSiegeEventPlugIn.TryGetContext(player.GameContext);
+        if (context is null)
+        {
+            await ShowAsync(player, "Castle Siege is not active on this server.").ConfigureAwait(false);
+            return;
+        }
+
+        if (player.GuildStatus is not { } guildStatus)
+        {
+            await ShowAsync(player, "Only members of a registered guild can take the throne.").ConfigureAwait(false);
+            return;
+        }
+
+        var guildName = guildStatus.GuildId.ToString();
+        if (player.GameContext is IGameServerContext serverContext)
+        {
+            var guild = await serverContext.GuildServer.GetGuildAsync(guildStatus.GuildId).ConfigureAwait(false);
+            if (guild?.Name is { Length: > 0 } name)
+            {
+                guildName = name;
+            }
+        }
+
+        if (!context.RegisteredGuilds.Contains(guildName))
+        {
+            await ShowAsync(player, "Your guild is not registered for this Castle Siege.").ConfigureAwait(false);
+            return;
+        }
+
+        var (success, reason) = context.TryCaptureThrone(guildName);
+        if (success)
+        {
+            await player.GameContext.ForEachPlayerAsync(p =>
+                p.InvokeViewPlugInAsync<IShowMessagePlugIn>(v =>
+                    v.ShowMessageAsync($"Guild '{guildName}' has CAPTURED THE THRONE! They will win the castle if they hold it until the siege ends.", MessageType.GoldenCenter)).AsTask()).ConfigureAwait(false);
+        }
+        else
+        {
+            await ShowAsync(player, reason).ConfigureAwait(false);
+        }
+    }
+
+    private static ValueTask ShowAsync(Player player, string text)
+        => player.InvokeViewPlugInAsync<IShowMessagePlugIn>(p => p.ShowMessageAsync(text, MessageType.BlueNormal));
+}

src/GameLogic/PlugIns/PeriodicTasks/CastleSiegeEventPlugIn.cs

@@ -30,12 +30,14 @@ public sealed class CastleSiegeEventPlugIn : IPeriodicTaskPlugIn, ISupportCustom
     private const int SwitchHoldRange = 3;
 
     // Castle defenses spawned at siege start — destructibles the attackers must break: (number, x, y).
+    // Positions are in the throne-room area (near the crown ~176,212 and the switches ~167-184,194-195),
+    // where players can actually reach and hit them (the earlier statue spot 170/182,206 was confirmed reachable).
     private static readonly (short Number, byte X, byte Y)[] DefenseSpawns =
     {
-        (CastleGateNumber, 160, 180),
-        (CastleGateNumber, 190, 180),
-        (GuardianStatueNumber, 170, 206),
-        (GuardianStatueNumber, 182, 206),
+        (CastleGateNumber, 168, 200),
+        (CastleGateNumber, 184, 200),
+        (GuardianStatueNumber, 170, 208),
+        (GuardianStatueNumber, 182, 208),
     };
 
     // Crown Switch positions on Valley of Loren (from the map init) — held by standing on them: (number, x, y).
@@ -209,12 +211,6 @@ public sealed class CastleSiegeEventPlugIn : IPeriodicTaskPlugIn, ISupportCustom
 
                 context.SetSwitchHolder(switchNumber, holder);
             }
-
-            var captured = context.EvaluateCapture();
-            if (captured is not null)
-            {
-                await AnnounceAsync(gameContext, $"Guild '{captured}' has CAPTURED THE THRONE! They win the castle if they hold it until the siege ends.").ConfigureAwait(false);
-            }
         }
         catch (Exception ex)
         {