fix(ext/node): windows cancel stdin read in line mode (#23969)

This patch fixes stdin read hanging on user input when switching tty
mode on Windows

Fixes #21111

On Windows, when switching from line to raw mode:
- Cancel ongoing console read by writing a return keypress to its input
buffer. This blocks the main thread until any ongoing read has been
cancelled to prevent interference with the screen state.
- On the read thread, restore the cursor position to where it was before
writing the enter, undoing its effect on the screen state.
- Restart reading and notify the main thread.

1 files changed, 21 insertions, 0 deletions

diff --git a/tests/testdata/run/process_stdin_unblock.mjs b/tests/testdata/run/process_stdin_unblock.mjs
new file mode 100644
index 000000000..bbeea2afb
--- /dev/null
+++ b/tests/testdata/run/process_stdin_unblock.mjs
@@ -0,0 +1,21 @@
+import process from "node:process";
+
+function prompt() {
+  process.stdin.setRawMode(true);
+
+  const { promise, resolve } = Promise.withResolvers();
+
+  const onData = (buf) => {
+    process.stdin.setRawMode(false);
+    process.stdin.removeListener("data", onData);
+    console.log(buf.length);
+    resolve();
+  };
+
+  process.stdin.on("data", onData);
+  return promise;
+}
+
+await prompt();
+await prompt();
+Deno.exit(0);