Add phase 1 critical import tool

src/RolemasterDb.ImportTool/RepositoryPaths.cs

@@ -0,0 +1,34 @@
+namespace RolemasterDb.ImportTool;
+
+public sealed class RepositoryPaths
+{
+    private RepositoryPaths(string rootPath)
+    {
+        RootPath = rootPath;
+        ManifestPath = Path.Combine(rootPath, "sources", "critical-import-manifest.json");
+        DefaultDatabasePath = Path.Combine(rootPath, "src", "RolemasterDb.App", "rolemaster.db");
+        ArtifactsRootPath = Path.Combine(rootPath, "artifacts", "import", "critical");
+    }
+
+    public string RootPath { get; }
+    public string ManifestPath { get; }
+    public string DefaultDatabasePath { get; }
+    public string ArtifactsRootPath { get; }
+
+    public static RepositoryPaths Discover()
+    {
+        var probe = new DirectoryInfo(Directory.GetCurrentDirectory());
+
+        while (probe is not null)
+        {
+            if (File.Exists(Path.Combine(probe.FullName, "RolemasterDB.slnx")))
+            {
+                return new RepositoryPaths(probe.FullName);
+            }
+
+            probe = probe.Parent;
+        }
+
+        throw new InvalidOperationException("Could not discover the repository root from the current directory.");
+    }
+}