fix: terminal hangs, right arrow blocking, and runaway iris processes (#142)

closes #137

- right arrow consumed the escape sequence without forwarding it, so the
cursor couldn't move back right after moving left (60149a2)
- p10k's instant prompt redirects stdout to a temp file that exec iris
inherits, sending the overlay there instead of the terminal and looking
like a dead keyboard. Reopens /dev/tty when stdout isn't a terminal
(7ebbb0c)
- zsh/bash autostart lacked the interactivity check fish already had, so
agentic tools sourcing your rc file spawned a rogue iris that seized
/dev/tty (5fe58be)

root/wrapper_test.go

@@ -4,6 +4,8 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+
+	"golang.org/x/term"
 )
 
 func wantDir(t *testing.T, path string) string {
@@ -24,6 +26,55 @@ func currentDir(t *testing.T) string {
 	return wantDir(t, cwd)
 }
 
+func TestRestoreStdoutTTYRedirectsFileStdoutToTerminal(t *testing.T) {
+	tty, err := os.OpenFile("/dev/tty", os.O_WRONLY, 0)
+	if err != nil {
+		t.Skip("no controlling terminal available")
+	}
+	_ = tty.Close()
+
+	// stand in for the temp file powerlevel10k's instant prompt leaves on stdout
+	redirected, err := os.CreateTemp(t.TempDir(), "instant-prompt-output")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = redirected.Close() }()
+
+	original := os.Stdout
+	os.Stdout = redirected
+	t.Cleanup(func() { os.Stdout = original })
+
+	restoreStdoutTTY()
+
+	if os.Stdout == redirected {
+		t.Fatal("restoreStdoutTTY left stdout pointing at the redirected file")
+	}
+	if !term.IsTerminal(int(os.Stdout.Fd())) {
+		t.Fatal("restoreStdoutTTY did not leave stdout on a terminal")
+	}
+	_ = os.Stdout.Close()
+}
+
+func TestRestoreStdoutTTYKeepsExistingTerminal(t *testing.T) {
+	tty, err := os.OpenFile("/dev/tty", os.O_WRONLY, 0)
+	if err != nil {
+		t.Skip("no controlling terminal available")
+	}
+
+	original := os.Stdout
+	os.Stdout = tty
+	t.Cleanup(func() {
+		os.Stdout = original
+		_ = tty.Close()
+	})
+
+	restoreStdoutTTY()
+
+	if os.Stdout != tty {
+		t.Fatal("restoreStdoutTTY reopened stdout that was already a terminal")
+	}
+}
+
 func TestSyncProcessCWDFollowsShell(t *testing.T) {
 	shellDir := t.TempDir()
 	t.Chdir(t.TempDir())