Fix build script and API usage

- Add all required assembly references (mscorlib, netstandard, System.dll, System.Core.dll)
- Use GameManager.ChatMessageServer instead of NetPackageChat
- Use Log.Out (proper 7DTD API) instead of Debug.Log

build.sh

@@ -5,6 +5,10 @@ GAME_DIR="${GAME_DIR:-$HOME/.local/share/7DaysToDie}"
 
 mcs -target:library \
     -out:BotCommandMod.dll \
+    -r:"$GAME_DIR/7DaysToDie_Data/Managed/mscorlib.dll" \
+    -r:"$GAME_DIR/7DaysToDie_Data/Managed/netstandard.dll" \
+    -r:"$GAME_DIR/7DaysToDie_Data/Managed/System.dll" \
+    -r:"$GAME_DIR/7DaysToDie_Data/Managed/System.Core.dll" \
     -r:"$GAME_DIR/7DaysToDie_Data/Managed/Assembly-CSharp.dll" \
     -r:"$GAME_DIR/7DaysToDie_Data/Managed/UnityEngine.CoreModule.dll" \
     -r:"$GAME_DIR/7DaysToDie_Data/Managed/0Harmony.dll" \