feat(chat): port retail's @pklite client command (EnterPkLite 0x028F)

acdream never implemented @pklite. It is a CLIENT command in retail, not a
server one — ACE has no pklite text-command handler — so typing it forwarded as
inert chat text that the server ignored.

Retail: ClientCommunicationSystem::DoPKLite @0x0057A490 rejects with
WeenieError 0x507 when ACCWeenieObject::IsPlayerKiller @0x0058C910 is true
(that returns true when EITHER the PK bit 0x20 OR the PKLite bit 0x2000000 is
set), prints "Please see @help pklite for more..." and sends nothing if given
any argument text, and otherwise calls CM_Character::Event_EnterPKLite
@0x006A13F0 — a bare 12-byte parameterless game action, opcode 0x28F, the same
shape as Event_LoginCompleteNotification beside it. Verb string at 0x007E16B0,
help text at 0x007DF0C8, failure string at 0x007D31E8; one verb, no alias.

HasPlayerFlag is a tri-state (null = the local PublicWeenieDesc has not
arrived). The existing arena gates compare `== false` because they reject on a
known-FALSE flag; retail's DoPKLite gates the other way, rejecting on
known-TRUE. So this case compares `== true` on either bit: an indeterminate
description sends rather than blocks, which matches retail trusting the server
instead of inventing a client-side suppression rule.

Landed as its own commit because it is retail-faithful on its own merits, but
the motivation is C4 route 2: ACE advances SequenceType.ObjectForcePosition in
exactly two places, and the only reachable one is Player.HandleActionEnterPkLite's
entry-collision bump (allow_pkl_bump, default on). Every admin teleport advances
ObjectTeleport instead, so @teleto-style displacement exercises route 3, not
route 2. Without this command route 2 has no connected acceptance gate at all.

Gates: complete Release solution 10,867 passed / 4 skipped / 0 failed
(9966b531 baseline 10,858/4/0; +9 = the 9 tests added). Coverage includes both
known-true rejections, the known-false success case, the tri-state unknown
case, the 12-byte wire envelope, and @pklite resolving as ClientHandled rather
than falling through to the server-text path.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/AcDream.Core.Net/Messages/ClientCommandRequests.cs

@@ -14,6 +14,7 @@ public static class ClientCommandRequests
     public const uint MarketplaceOpcode = 0x028Du;
     public const uint PkArenaOpcode = 0x0027u;
     public const uint PkLiteArenaOpcode = 0x0026u;
+    public const uint EnterPkLiteOpcode = 0x028Fu;
     public const uint HouseRecallOpcode = 0x0262u;
     public const uint MansionRecallOpcode = 0x0278u;
     public const uint QueryAgeOpcode = 0x01C2u;
@@ -54,6 +55,11 @@ public static class ClientCommandRequests
     public static byte[] BuildPkLiteArena(uint sequence) =>
         BuildParameterless(sequence, PkLiteArenaOpcode);
 
+    // CM_Character::Event_EnterPKLite @ 0x006A13F0 — 12-byte parameterless
+    // game action, opcode 0x28F, identical shape to Event_LoginCompleteNotification.
+    public static byte[] BuildEnterPkLite(uint sequence) =>
+        BuildParameterless(sequence, EnterPkLiteOpcode);
+
     public static byte[] BuildHouseRecall(uint sequence) =>
         BuildParameterless(sequence, HouseRecallOpcode);
 

src/AcDream.Core.Net/WorldSession.cs

@@ -2102,6 +2102,13 @@ public sealed class WorldSession : IDisposable
         SendGameAction(ClientCommandRequests.BuildPkLiteArena(seq));
     }
 
+    /// <summary>Send retail @pklite / Enter PK Lite request (0x028F).</summary>
+    public void SendEnterPkLite()
+    {
+        uint seq = NextGameActionSequence();
+        SendGameAction(ClientCommandRequests.BuildEnterPkLite(seq));
+    }
+
     /// <summary>Send retail personal-house recall (0x0262).</summary>
     public void SendTeleportToHouse()
     {