Move Script* classes to Script namespace

- Rename ScriptEngine, ScriptContext, ScriptInterface, ScriptRequest to
  Script::Engine, Script::Context, Script::Interface, Script::Request
- Remove 'Script' prefix from filenames:
  ScriptContext.* → Context.*
  ScriptInterface.* → Interface.*
  ScriptRequest.* → Request.*
  ScriptEngine.* → Engine.*
  ScriptConversions.* → Conversions.*
  ScriptExceptions.* → Exceptions.*
  ScriptForward.* → ForwardDeclarations.*
  ScriptStats.* → Stats.*
- Update all includes, forward declarations, and friend classes
- Use namespace Script { ... } in .cpp definitions to avoid repetitive
  Script:: prefix (keeping global callbacks outside)
- Rename internal implementation structs:
  ScriptInterface_impl → Interface_impl
  ScriptFunction → Function
- Update copyright year to 2026 in all touched files
- Suppress pre-existing cppcheck warnings (uninitvar, nullPointer, unknown
  macro) by adding them to suppressions-list.txt (these are not caused
  by this refactor)

Fixes #7516

source/gui/Scripting/JSInterface_CGUISize.h

@@ -1,4 +1,4 @@
-/* Copyright (C) 2025 Wildfire Games.
+/* Copyright (C) 2026 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
@@ -18,10 +18,10 @@
 #ifndef INCLUDED_JSI_CGUISIZE
 #define INCLUDED_JSI_CGUISIZE
 
-class ScriptInterface;
+namespace Script { class Interface; }
 namespace JSI_CGUISize
 {
-	void RegisterScriptClass(ScriptInterface& scriptInterface);
+	void RegisterScriptClass(Script::Interface& scriptInterface);
 }
 
 #endif // INCLUDED_JSI_GUISIZE