fix(resident): drop stdout redirect to unblock parent on Windows

Redirecting the resident child's stdout caused Windows CreateProcess
to set bInheritHandles=TRUE, leaking the outer shell's pipe handle
into the resident. The shell then blocked for ~60s waiting for EOF
on a pipe the resident still owned, even though officecli main had
already exited.

- Remove RedirectStandardOutput from the resident ProcessStartInfo
  (stderr redirect is kept for startup failure diagnostics)
- Dispose the Process on all exit paths (success/exited/timeout) to
  release the remaining pipe handle promptly
- Wrap resident-side background Console.Error.WriteLine calls in a
  LogStderr helper that swallows IOException, so the resident does
  not crash when writing diagnostics to a stderr pipe whose read-end
  was closed by the parent exiting

src/officecli/CommandBuilder.cs

@@ -166,7 +166,11 @@ static partial class CommandBuilder
             Arguments = $"__resident-serve__ \"{filePath}\"",
             UseShellExecute = false,
             CreateNoWindow = true,
-            RedirectStandardOutput = true,
+            // Do NOT redirect stdout: on Windows, RedirectStandardOutput
+            // causes bInheritHandles=TRUE which leaks the outer shell's
+            // pipe handle into the resident, blocking the caller for ~60s
+            // until the resident's idle timeout.  Stderr is still redirected
+            // to capture diagnostics if the resident fails during startup.
             RedirectStandardError = true
         };
 
@@ -185,16 +189,21 @@ static partial class CommandBuilder
         {
             Thread.Sleep(100);
             if (ResidentClient.TryConnect(filePath, out _))
+            {
+                process.Dispose();
                 return true;
+            }
             if (process.HasExited)
             {
                 var stderr = process.StandardError.ReadToEnd();
                 error = $"Resident process exited. {stderr}";
+                process.Dispose();
                 return false;
             }
         }
 
         error = "Resident process started but not responding.";
+        process.Dispose();
         return false;
     }
 

src/officecli/ResidentServer.cs

@@ -43,6 +43,15 @@ public class ResidentServer : IDisposable
     private CancellationTokenSource _idleCts = new();
     private bool _disposed;
 
+    // Safe stderr logging: the parent process may have redirected our stderr
+    // to a pipe whose read-end closes when the parent exits, so any
+    // Console.Error.WriteLine after that point throws IOException.  Swallow
+    // it silently — these are best-effort diagnostics, not critical output.
+    private static void LogStderr(string message)
+    {
+        try { Console.Error.WriteLine(message); } catch (IOException) { }
+    }
+
     // Valid idle-timeout range: 1s .. 24h. Anything outside falls back to
     // the 12min default. A value of "0" is rejected (would be an infinite-
     // busy spin on the watchdog task). Shared between the startup env-var
@@ -203,7 +212,7 @@ public class ResidentServer : IDisposable
                 }
                 catch (Exception ex)
                 {
-                    Console.Error.WriteLine($"Resident error: {ex.Message}");
+                    LogStderr($"Resident error: {ex.Message}");
                     // currentMain is still the pre-created replacement; it is
                     // still valid for the next iteration's WaitForConnectionAsync.
                 }
@@ -258,7 +267,7 @@ public class ResidentServer : IDisposable
                 // cancelling _mainCts / _pingCts, so the "ping liveness ⇔
                 // file locked" invariant is preserved end-to-end: the
                 // ping pipe stays alive until handler.Dispose() completes.
-                Console.Error.WriteLine($"Resident idle for {currentTimeout.TotalMinutes} minutes, closing.");
+                LogStderr($"Resident idle for {currentTimeout.TotalMinutes} minutes, closing.");
                 _ = ShutdownAsync();
                 break;
             }
@@ -317,7 +326,7 @@ public class ResidentServer : IDisposable
                 }
                 catch (Exception ex)
                 {
-                    Console.Error.WriteLine($"Ping responder error: {ex.Message}");
+                    LogStderr($"Ping responder error: {ex.Message}");
                     // currentMain/current is already the replacement;
                     // loop continues.
                 }
@@ -383,7 +392,7 @@ public class ResidentServer : IDisposable
                 try { await ShutdownAsync(); }
                 catch (Exception ex)
                 {
-                    Console.Error.WriteLine($"Shutdown error during __close__: {ex.Message}");
+                    LogStderr($"Shutdown error during __close__: {ex.Message}");
                 }
 
                 var response = MakeResponse(0, "Closing resident.", "");
@@ -397,7 +406,7 @@ public class ResidentServer : IDisposable
         catch (OperationCanceledException) { }
         catch (Exception ex)
         {
-            Console.Error.WriteLine($"Ping handler error: {ex.Message}");
+            LogStderr($"Ping handler error: {ex.Message}");
         }
         finally
         {
@@ -424,7 +433,7 @@ public class ResidentServer : IDisposable
         catch (OperationCanceledException) { }
         catch (Exception ex)
         {
-            Console.Error.WriteLine($"Resident error: {ex.Message}");
+            LogStderr($"Resident error: {ex.Message}");
         }
         finally
         {
@@ -1091,13 +1100,13 @@ public class ResidentServer : IDisposable
         {
             if (!ShutdownAsync().Wait(TimeSpan.FromMinutes(10)))
             {
-                Console.Error.WriteLine("Warning: shutdown timed out after 10 minutes, forcing exit.");
+                LogStderr("Warning: shutdown timed out after 10 minutes, forcing exit.");
                 Environment.Exit(1);
             }
         }
         catch (Exception ex)
         {
-            Console.Error.WriteLine($"Warning: shutdown error: {ex.Message}");
+            LogStderr($"Warning: shutdown error: {ex.Message}");
         }
 
         try { _commandLock.Dispose(); } catch { }
@@ -1160,7 +1169,7 @@ public class ResidentServer : IDisposable
             }
             else
             {
-                Console.Error.WriteLine("Warning: timeout waiting for in-flight command to drain.");
+                LogStderr("Warning: timeout waiting for in-flight command to drain.");
             }
         }
         catch (ObjectDisposedException) { /* _commandLock already disposed */ }
@@ -1172,7 +1181,7 @@ public class ResidentServer : IDisposable
         try { _handler.Dispose(); }
         catch (Exception ex)
         {
-            Console.Error.WriteLine($"Warning: handler dispose error: {ex.Message}");
+            LogStderr($"Warning: handler dispose error: {ex.Message}");
         }
 
         // 5. NOW cancel ping + idle. Clients observing the ping pipe from