fix(pty): make terminal cleanup complete under backpressure

Cargo.toml

@@ -36,7 +36,7 @@ windows-sys = { version = "0.61.2", features = [
 ] }
 
 [target.'cfg(windows)'.dev-dependencies]
-windows-sys = { version = "0.61.2", features = ["Win32_System_Console"] }
+windows-sys = { version = "0.61.2", features = ["Win32_System_Console", "Win32_System_Threading"] }
 
 [profile.release]
 codegen-units = 1

README.md

@@ -269,6 +269,23 @@ multiple connections, namespace ownership, cancellation, and final-frame
 completion. These checks do not yet establish Windows daemon support or
 complete ConPTY shutdown behavior.
 
+On Windows, normal root-child exit hands the ConPTY master to the existing
+child-wait worker for closing. The actor and reader continue draining until the
+real output-pipe EOF; only then is the final exit event published. The worker
+checks the root's wait handle at 10 ms intervals. After the master is handed
+off, Windows input and resize requests fail with a child-exited error; final
+snapshots, rows, and replay remain readable until the terminal is removed.
+Unix post-exit PTY operations retain their existing behavior.
+
+### Known Linux cleanup limitation
+
+A child that exits without consuming a large queued PTY write can leave the
+Linux master write blocked after the child, actor, reader, and waiter have
+already stopped. `TerminalService::terminate` or service drop can then wait
+indefinitely for the writer thread. This pre-existing Unix I/O limitation is
+not repaired by the Windows cleanup work. A test watchdog or the daemon's
+forced-exit deadline does not prove that those worker threads were joined.
+
 Once the workflow is on `master`, it can also be run manually against a branch:
 
 ```sh