Move rolling stock and physics into the domain

VehicleDatabase becomes VehicleCatalog, Physics becomes VehiclePhysics, and the
textures.txt and .fiz parsers move to Infrastructure. GameLibrary replaces the
GameData singleton.

StarterNG/Infrastructure/Vehicles/TexturesTxtVehicleRepository.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using StarterNG.Application.Abstractions;
+using StarterNG.Domain.Vehicles;
+
+namespace StarterNG.Infrastructure.Vehicles;
+
+/// <summary>
+/// Loads the catalogue from the dynamic/&lt;maker&gt;/&lt;vehicle&gt;/textures.txt
+/// files an installation ships.
+/// </summary>
+public sealed class TexturesTxtVehicleRepository : IVehicleRepository
+{
+    private const string TexturesFileName = "textures.txt";
+
+    private readonly IFileSystem _files;
+    private readonly IGamePaths _paths;
+    private readonly IDiagnosticsLog _log;
+    private readonly TexturesTxtParser _parser;
+    private readonly Encoding _encoding;
+
+    public TexturesTxtVehicleRepository(IFileSystem files, IGamePaths paths, IDiagnosticsLog log,
+                                        TexturesTxtParser parser)
+    {
+        _files = files;
+        _paths = paths;
+        _log = log;
+        _parser = parser;
+        _encoding = LegacyEncoding();
+    }
+
+    public int Load(VehicleCatalog catalog)
+    {
+        catalog.BeginLoad();
+
+        int liveries = 0;
+        foreach (string file in TexturesFiles())
+        {
+            var entry = ReadEntry(file);
+            if (entry is null)
+                continue;
+
+            liveries += entry.Textures.Count;
+            catalog.Ingest(entry);
+        }
+
+        catalog.EndLoad();
+        return liveries;
+    }
+
+    private VehicleEntry? ReadEntry(string path)
+    {
+        try
+        {
+            // Read as text so the code page survives: the credit lines carry
+            // Polish characters that ReadAllLines' default encoding would mangle.
+            string[] lines = _files.ReadAllText(path, _encoding).Split('\n');
+            return _parser.Parse(RelativeDirectory(path), lines);
+        }
+        catch (Exception ex)
+        {
+            _log.Log($"textures.txt {path}", ex);
+            return null;
+        }
+    }
+
+    /// <summary>
+    /// Rolling stock sits exactly two levels below dynamic/: a maker folder and a
+    /// vehicle folder.
+    /// </summary>
+    private IEnumerable<string> TexturesFiles()
+    {
+        foreach (string maker in _files.GetDirectories(_paths.Dynamic))
+        foreach (string vehicle in _files.GetDirectories(maker))
+        {
+            string path = Path.Combine(vehicle, TexturesFileName);
+            if (_files.FileExists(path))
+                yield return path;
+        }
+    }
+
+    /// <summary>
+    /// The folder as the scenery format spells it: relative to dynamic/, forward
+    /// slashes, trailing slash.
+    /// </summary>
+    private string RelativeDirectory(string texturesPath)
+    {
+        string directory = Path.GetDirectoryName(texturesPath) ?? "";
+        string full = Path.GetFullPath(directory);
+        string root = Path.GetFullPath(_paths.Dynamic);
+
+        string relative = full.StartsWith(root, StringComparison.OrdinalIgnoreCase)
+            ? full[root.Length..].TrimStart(Path.DirectorySeparatorChar, '/')
+            : directory;
+
+        return relative.Replace('\\', '/').TrimEnd('/') + "/";
+    }
+
+    private static Encoding LegacyEncoding()
+    {
+        try
+        {
+            return Encoding.GetEncoding(1250);
+        }
+        catch (Exception)
+        {
+            return Encoding.Latin1;
+        }
+    }
+}