chore(cli): scaffold CLI project with option parsing

src/Chip8.Cli/Chip8.Cli.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>disable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <RootNamespace>Chip8.Cli</RootNamespace>
+    <AssemblyName>Chip8.Cli</AssemblyName>
+    <LangVersion>10</LangVersion>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Raylib-cs" Version="4.5.0.4" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\Chip8.Core\Chip8.Core.csproj" />
+  </ItemGroup>
+
+</Project>

src/Chip8.Cli/Options.cs

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+using System;
+using Chip8.Core;
+
+namespace Chip8.Cli;
+
+sealed class Options
+{
+    public string romPath = "";
+    public bool headless;
+    public int cycles = 2000;
+    public int scale = 14;
+    public int instructionsPerFrame = 11;
+    public int? seed;
+    public string quirksProfile = "auto";
+    public string platformName = "chip8";
+    public string paletteName = "octo";
+    public int maxFrames;
+    public string? screenshotPath;
+    public string? dumpPpmPath;
+    public string? dumpWavPath;
+
+    public Platform buildPlatform() => platformName.ToLowerInvariant() switch
+    {
+        "superchip" or "schip" => Platform.SuperChip,
+        "xochip" or "xo" => Platform.XoChip,
+        _ => Platform.Chip8,
+    };
+
+    public Quirks? buildQuirks() => quirksProfile.ToLowerInvariant() switch
+    {
+        "auto" => null,
+        "cosmac" => Quirks.cosmacVip(),
+        "superchip" => Quirks.superChip(),
+        "xochip" => Quirks.xoChip(),
+        _ => Quirks.modern(),
+    };
+
+    public Palette buildPalette() => Palette.byName(paletteName);
+
+    public static Options parse(string[] args)
+    {
+        var options = new Options();
+        int index = 0;
+
+        while (index < args.Length)
+        {
+            string token = args[index];
+            switch (token)
+            {
+                case "--headless":
+                    options.headless = true;
+                    index++;
+                    break;
+                case "--cycles":
+                    options.cycles = int.Parse(args[++index]);
+                    index++;
+                    break;
+                case "--scale":
+                    options.scale = int.Parse(args[++index]);
+                    index++;
+                    break;
+                case "--ipf":
+                    options.instructionsPerFrame = int.Parse(args[++index]);
+                    index++;
+                    break;
+                case "--seed":
+                    options.seed = int.Parse(args[++index]);
+                    index++;
+                    break;
+                case "--quirks":
+                    options.quirksProfile = args[++index];
+                    index++;
+                    break;
+                case "--platform":
+                    options.platformName = args[++index];
+                    index++;
+                    break;
+                case "--palette":
+                    options.paletteName = args[++index];
+                    index++;
+                    break;
+                case "--frames":
+                    options.maxFrames = int.Parse(args[++index]);
+                    index++;
+                    break;
+                case "--shot":
+                    options.screenshotPath = args[++index];
+                    index++;
+                    break;
+                case "--ppm":
+                    options.dumpPpmPath = args[++index];
+                    index++;
+                    break;
+                case "--wav":
+                    options.dumpWavPath = args[++index];
+                    index++;
+                    break;
+                default:
+                    if (token.StartsWith("--"))
+                    {
+                        throw new ArgumentException($"Unknown option: {token}");
+                    }
+                    options.romPath = token;
+                    index++;
+                    break;
+            }
+        }
+
+        if (options.romPath.Length == 0)
+        {
+            throw new ArgumentException("No ROM path given.");
+        }
+
+        return options;
+    }
+}