refactor: drop the remaining single-implementation interfaces

IBaseDirtyChecker, IInteractiveLaunchSpecService and the LaunchSpec wrapper
had one implementation and one caller each; ProcessRunnerAdapter existed only
to give a static class an interface, and InstallArtifactLocator used
inheritance for two constructor arguments. The external MCP container now
shares its singletons through a Share<T> helper instead of 17 near-identical
registrations.

src/ClaudeDo.Ui/Services/InstallArtifactLocator.cs

@@ -1,29 +1,19 @@
 namespace ClaudeDo.Ui.Services;
 
-public sealed class InstallerLocator : InstallArtifactLocator
-{
-    protected override string Subdir => "uninstaller";
-    protected override string ExeName => "ClaudeDo.Installer.exe";
-}
+// Two named types because DI resolves them by type, not by key.
+public sealed class InstallerLocator() : InstallArtifactLocator("uninstaller", "ClaudeDo.Installer.exe");
 
-public sealed class WorkerLocator : InstallArtifactLocator
-{
-    protected override string Subdir => "worker";
-    protected override string ExeName => "ClaudeDo.Worker.exe";
-}
+public sealed class WorkerLocator() : InstallArtifactLocator("worker", "ClaudeDo.Worker.exe");
 
 /// <summary>
 /// Locates an executable inside a ClaudeDo install: walk up from the running
 /// directory to the folder containing install.json, otherwise read the
-/// uninstall registry key. Subclasses supply the subdirectory and exe name.
+/// uninstall registry key (which is what makes this work from a dev build).
 /// </summary>
-public abstract class InstallArtifactLocator
+public abstract class InstallArtifactLocator(string subdir, string exeName)
 {
     private const string InstallJson = "install.json";
 
-    protected abstract string Subdir { get; }
-    protected abstract string ExeName { get; }
-
     public string? Find()
         => FindByWalkingUp(AppContext.BaseDirectory)
            ?? (OperatingSystem.IsWindows() ? FindByRegistry() : null);
@@ -34,10 +24,7 @@ public abstract class InstallArtifactLocator
         while (dir is not null)
         {
             if (File.Exists(Path.Combine(dir.FullName, InstallJson)))
-            {
-                var candidate = Path.Combine(dir.FullName, Subdir, ExeName);
-                return File.Exists(candidate) ? candidate : null;
-            }
+                return Candidate(dir.FullName);
             dir = dir.Parent;
         }
         return null;
@@ -52,10 +39,14 @@ public abstract class InstallArtifactLocator
             using var key = Microsoft.Win32.Registry.LocalMachine
                 .OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Uninstall\ClaudeDo");
             var location = key?.GetValue("InstallLocation") as string;
-            if (string.IsNullOrEmpty(location)) return null;
-            var candidate = Path.Combine(location, Subdir, ExeName);
-            return File.Exists(candidate) ? candidate : null;
+            return string.IsNullOrEmpty(location) ? null : Candidate(location);
         }
         catch { return null; }
     }
+
+    private string? Candidate(string installDir)
+    {
+        var path = Path.Combine(installDir, subdir, exeName);
+        return File.Exists(path) ? path : null;
+    }
 }