Fix Remote Braille ordering and lease cleanup

internal/app/tentacle_remote_braille.go

@@ -9,7 +9,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"io"
+	"os"
 	"os/exec"
 	"slices"
 	"time"
@@ -29,7 +29,7 @@ type virtualBraille interface {
 
 type processVirtualBraille struct {
 	cmd       *exec.Cmd
-	stdin     io.WriteCloser
+	stdin     *os.File
 	encoder   *json.Encoder
 	responses chan braille.VirtualResponse
 	done      chan struct{}
@@ -45,12 +45,13 @@ func start_virtual_braille(path string) (virtualBraille, error) {
 	}
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
+		_ = stdin.Close()
 		return nil, err
 	}
 	if err := cmd.Start(); err != nil {
 		return nil, err
 	}
-	helper := &processVirtualBraille{cmd: cmd, stdin: stdin, encoder: json.NewEncoder(stdin),
+	helper := &processVirtualBraille{cmd: cmd, stdin: stdin.(*os.File), encoder: json.NewEncoder(stdin),
 		responses: make(chan braille.VirtualResponse, 16), done: make(chan struct{})}
 	go func() {
 		defer close(helper.responses)
@@ -72,6 +73,10 @@ func start_virtual_braille(path string) (virtualBraille, error) {
 }
 
 func (helper *processVirtualBraille) Send(request braille.VirtualRequest) error {
+	// A wedged translator must not prevent lease cleanup or owner shutdown.
+	if err := helper.stdin.SetWriteDeadline(time.Now().Add(time.Second)); err != nil {
+		return err
+	}
 	return helper.encoder.Encode(request)
 }
 
@@ -197,9 +202,7 @@ func (runtime *tentacleRuntime) start_remote_braille(ctx context.Context, sessio
 							continue
 						}
 						helper, responses, exportLease, exportDone = started, started.Responses(), delivery.Lease, delivery.Context.Done()
-						if frame, ok := worker.SetRemoteExport(offer); ok {
-							offer(frame)
-						}
+						worker.SetRemoteExport(offer)
 					}
 					width := value.Width
 					if helper.Send(braille.VirtualRequest{Width: &width}) != nil {
@@ -240,7 +243,11 @@ func (runtime *tentacleRuntime) start_remote_braille(ctx context.Context, sessio
 					continue
 				}
 				if response.Route != nil {
-					worker.RouteExported(ctx, *response.Route)
+					// A buffered helper response can race lease revocation.
+					leaseCtx, err := session.RemoteContext(exportLease, "braille-stream")
+					if err == nil && allowed() {
+						worker.RouteExported(leaseCtx, *response.Route)
+					}
 				} else if len(response.Cells) != 0 && allowed() {
 					if errors.Is(session.PublishRemoteBraille(exportLease, tentaclewire.RemoteBraille{Op: "cells", Cells: response.Cells}), tentacle.ErrLimit) {
 						stopExport()