partial linux setup/install scripting

Launcher/WiiCompiled.Setup.Linux/WorkspaceLocator.cs

@@ -0,0 +1,27 @@
+namespace WiiCompiled.Setup.Linux;
+
+/// <summary>
+/// Finds the repo checkout this tool is running from by walking up from its own directory looking
+/// for Launcher/local-build.sh - this tool operates directly on a git checkout (no bundled/staged
+/// workspace copy), so there is no installed "Toolkit" layout to anchor on the way the Windows
+/// installer's Installation.cs does.
+/// </summary>
+internal static class WorkspaceLocator
+{
+    private const int MaxSearchDepth = 6;
+
+    public static string FindFrom(string startDirectory)
+    {
+        var current = new DirectoryInfo(startDirectory);
+        for (var level = 0; level <= MaxSearchDepth && current is not null; level++, current = current.Parent)
+        {
+            if (File.Exists(Path.Combine(current.FullName, "Launcher", "local-build.sh")))
+            {
+                return current.FullName;
+            }
+        }
+        throw new InvalidOperationException(
+            "Could not find the WiiCompiled repository (looked for Launcher/local-build.sh walking up " +
+            $"from {startDirectory}). Pass --workspace <path-to-checkout> explicitly.");
+    }
+}