fix(worker): name quarantined prompt files and their replacements in the recovery Warn

PromptFileRecovery's orphan-quarantine log only reported a bare count, so a customized
merge-helper-execute.md silently stopped applying with no pointer to where it went. Log each
quarantined file's destination path, and for merge-helper-execute.md specifically call out that
it was split into merge-helper-wait.md and merge-helper-merge.md with no content migration.

tests/ClaudeDo.Worker.Tests/Lifecycle/PromptFileRecoveryTests.cs

@@ -1,12 +1,31 @@
 using System.Text.Json;
 using ClaudeDo.Data;
 using ClaudeDo.Worker.Lifecycle;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 
 namespace ClaudeDo.Worker.Tests.Lifecycle;
 
 public sealed class PromptFileRecoveryTests
 {
+    private sealed class CapturingLogger<T> : ILogger<T>
+    {
+        public List<string> Messages { get; } = new();
+
+        public IDisposable BeginScope<TState>(TState state) where TState : notnull => NullScope.Instance;
+        public bool IsEnabled(LogLevel logLevel) => true;
+
+        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception,
+            Func<TState, Exception?, string> formatter)
+            => Messages.Add(formatter(state, exception));
+
+        private sealed class NullScope : IDisposable
+        {
+            public static readonly NullScope Instance = new();
+            public void Dispose() { }
+        }
+    }
+
     [Fact]
     public async Task StartAsync_ReconcilesStaleDefaultAndQuarantinesOrphan_WithoutTouchingRealEdit()
     {
@@ -46,4 +65,33 @@ public sealed class PromptFileRecoveryTests
             if (Directory.Exists(root)) Directory.Delete(root, recursive: true);
         }
     }
+
+    [Fact]
+    public async Task StartAsync_QuarantinesOrphanedMergeHelperExecute_WarnNamesFileAndReplacements()
+    {
+        var root = Path.Combine(Path.GetTempPath(), $"claudedo_prompts_{Guid.NewGuid():N}");
+        try
+        {
+            Directory.CreateDirectory(root);
+            var orphanPath = Path.Combine(root, "merge-helper-execute.md");
+            File.WriteAllText(orphanPath, "my old customized triage+wait+merge prompt");
+
+            var logger = new CapturingLogger<PromptFileRecovery>();
+            var sut = new PromptFileRecovery(logger, root);
+
+            await sut.StartAsync(CancellationToken.None);
+
+            var dest = Path.Combine(root, "_orphans", "merge-helper-execute.md");
+            Assert.False(File.Exists(orphanPath));
+            Assert.True(File.Exists(dest));
+
+            Assert.Contains(logger.Messages, m => m.Contains("merge-helper-execute.md") && m.Contains(dest));
+            Assert.Contains(logger.Messages, m =>
+                m.Contains("merge-helper-wait.md") && m.Contains("merge-helper-merge.md"));
+        }
+        finally
+        {
+            if (Directory.Exists(root)) Directory.Delete(root, recursive: true);
+        }
+    }
 }