feat(net): #18 holtburger inbound chat parity - EmoteText, SoulEmote, ServerMessage, PlayerKilled, WeenieError + Windows-1252 codec

Five sub-changes:

1. Windows-1252 codec switch (global). Every Encoding.ASCII call site
   in src/AcDream.Core.Net/Messages/ -> Encoding.GetEncoding(1252).
   Touched HearSpeech, ChatRequests, GameEvents, AppraiseInfoParser,
   CharacterList, CreateObject, PlayerDescriptionParser, SocialActions.
   New Encodings.cs module-init registers CodePagesEncodingProvider
   (System.Text.Encoding.CodePages ships with .NET 10 SDK but isn't
   auto-registered). Matches retail + holtburger; accented names
   no longer round-trip-broken.

2. New parsers (opcodes confirmed against holtburger opcodes.rs):
   - EmoteText (0x01E0)     { u32 senderGuid, string16 senderName, string16 text }
   - SoulEmote (0x01E2)     same wire layout as EmoteText
   - ServerMessage (0xF7E0) { string16 message, u32 chatType }
   - PlayerKilled (0x019E)  { string16 deathMessage, u32 victimGuid, u32 killerGuid }
   Shared StringReader.cs has the CP1252 String16L primitive.

3. WorldSession dispatch. ProcessDatagram adds branches for the four
   new top-level opcodes + fires session-level events (EmoteHeard,
   SoulEmoteHeard, ServerMessageReceived, PlayerKilledReceived).
   0x0295 SetTurbineChatChannels stubbed with TODO for parallel I.6.

4. GameEventWiring routes WeenieError + WeenieErrorWithString
   (parsers existed but were unrouted) -> chat.OnWeenieError.

5. ChatLog adapters: Emote / SoulEmote ChatKind values, OnEmote,
   OnSoulEmote, OnPlayerKilled, OnWeenieError. OnLocalSpeech now
   substitutes empty sender -> "You" per holtburger client/messages.rs.
   ChatVM.FormatEntry handles new kinds (asterisk + sender + text).

22 new tests covering parser round-trips + reject-bad-opcode +
ChatLog adapter coverage + Win-1252 round-trip with non-ASCII chars.
Solution total: 881 green (210->225 in Core.Net.Tests, 606->613 in Core.Tests).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.UI.Abstractions/Panels/Chat/ChatVM.cs

@@ -77,6 +77,13 @@ public sealed class ChatVM
         ChatKind.Tell          => $"[Tell] {entry.Sender}: {entry.Text}",
         ChatKind.System        => $"[System] {entry.Text}",
         ChatKind.Popup         => $"[Popup] {entry.Text}",
+        // Phase I.5: emote rendering matches retail's leading-asterisk
+        // convention ("* Caith waves at you"). SoulEmote uses the same
+        // prefix; the difference between Emote and SoulEmote is which
+        // animation pairs with the chat line (handled by the renderer,
+        // not the formatter).
+        ChatKind.Emote         => $"* {entry.Sender} {entry.Text}",
+        ChatKind.SoulEmote     => $"* {entry.Sender} {entry.Text}",
         _                      => entry.Text,
     };
 }