export: fix render-ticket classification; export any sequence

Two export killers fixed and the feature surfaced properly:

- TicketArena::allocate() reaps finished fire-and-forget slots on every
  new submit, but RenderTask classified finished tickets by asking the
  arena for their kind/time afterwards - any ticket that completed
  before the next submit (all of them on the inline backend) failed
  with 'Render ticket reported an unexpected timestamp' and the export
  died after writing a header-only file. RenderTask now records each
  ticket's delivery key at submit time instead.
- File > Export becomes 导出序列 (all 8 locales): the dialog offers a
  sequence picker (any sequence in the project, the current one
  preselected) instead of silently exporting the current one, and the
  project bin's sequence context menu gains 导出序列 opening the same
  dialog. Engines expose sequence_entries / current_sequence_id /
  start_export_of.
- The export-project dialog drops its dead hand-typed path field (OK
  already asked the platform save dialog).
- New end-to-end test: a one-second sequence exports to a real
  H.264/AAC MP4 that probes and decodes back to the clip's content.

assets/i18n/de.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "Projektdatei exportieren…"
 "menu.file.save_as": "Speichern unter…"
 "menu.file.revert": "Wiederherstellen"
-"menu.file.export_media": "Medien exportieren…"
+"menu.file.export_media": "Sequenz exportieren…"
 "menu.file.project_properties": "Projekteigenschaften…"
 "menu.file.close": "Projekt schließen"
 "menu.file.quit": "Beenden"
@@ -389,6 +389,7 @@
 "project.export.format": "Projektformat"
 "export.format.placeholder": "Format auswählen…"
 "export.path": "Ausgabepfad"
+"export.sequence": "Sequenz"
 "export.run": "Exportieren"
 "export.hint": "Die Sequenz wird über den oaktask-Exportpfad exportiert; der Fortschritt wird im Dialog angezeigt."
 "export.progress.title": "Exportieren"
@@ -483,6 +484,7 @@
 "project.context.reveal_in_finder": "Im Finder anzeigen"
 "project.context.replace_footage": "Material ersetzen"
 "project.context.rename": "Umbenennen"
+"project.context.export_sequence": "Sequenz exportieren…"
 "project.context.delete": "Löschen"
 "project.context.open_in_new_tab": "In neuem Tab öffnen"
 "project.context.open_in_new_window": "In neuem Fenster öffnen"

assets/i18n/en-US.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "Export Project File…"
 "menu.file.save_as": "Save As…"
 "menu.file.revert": "Revert"
-"menu.file.export_media": "Export Media…"
+"menu.file.export_media": "Export Sequence…"
 "menu.file.project_properties": "Project Properties…"
 "menu.file.close": "Close Project"
 "menu.file.quit": "Quit"
@@ -387,6 +387,7 @@
 "project.export.format": "Project Format"
 "export.format.placeholder": "Select a format…"
 "export.path": "Output path"
+"export.sequence": "Sequence"
 "export.run": "Export"
 "export.hint": "The sequence is exported through the oaktask export path; progress is shown in the dialog."
 "export.progress.title": "Exporting"
@@ -481,6 +482,7 @@
 "project.context.reveal_in_finder": "Reveal in Finder"
 "project.context.replace_footage": "Replace Footage"
 "project.context.rename": "Rename"
+"project.context.export_sequence": "Export Sequence…"
 "project.context.delete": "Delete"
 "project.context.open_in_new_tab": "Open in New Tab"
 "project.context.open_in_new_window": "Open in New Window"

assets/i18n/es.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "Exportar archivo de proyecto…"
 "menu.file.save_as": "Guardar como…"
 "menu.file.revert": "Revertir"
-"menu.file.export_media": "Exportar medios…"
+"menu.file.export_media": "Exportar secuencia…"
 "menu.file.project_properties": "Propiedades del proyecto…"
 "menu.file.close": "Cerrar proyecto"
 "menu.file.quit": "Salir"
@@ -389,6 +389,7 @@
 "project.export.format": "Formato del proyecto"
 "export.format.placeholder": "Seleccionar un formato…"
 "export.path": "Ruta de salida"
+"export.sequence": "Secuencia"
 "export.run": "Exportar"
 "export.hint": "La secuencia se exporta a través de la ruta de exportación oaktask; el progreso se muestra en el diálogo."
 "export.progress.title": "Exportando"
@@ -483,6 +484,7 @@
 "project.context.reveal_in_finder": "Mostrar en Finder"
 "project.context.replace_footage": "Reemplazar material"
 "project.context.rename": "Cambiar nombre"
+"project.context.export_sequence": "Exportar secuencia…"
 "project.context.delete": "Eliminar"
 "project.context.open_in_new_tab": "Abrir en pestaña nueva"
 "project.context.open_in_new_window": "Abrir en ventana nueva"

assets/i18n/fr.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "Exporter un fichier projet…"
 "menu.file.save_as": "Enregistrer sous…"
 "menu.file.revert": "Restaurer"
-"menu.file.export_media": "Exporter les médias…"
+"menu.file.export_media": "Exporter la séquence…"
 "menu.file.project_properties": "Propriétés du projet…"
 "menu.file.close": "Fermer le projet"
 "menu.file.quit": "Quitter"
@@ -389,6 +389,7 @@
 "project.export.format": "Format du projet"
 "export.format.placeholder": "Sélectionner un format…"
 "export.path": "Chemin de sortie"
+"export.sequence": "Séquence"
 "export.run": "Exporter"
 "export.hint": "La séquence est exportée via le chemin d'exportation oaktask ; la progression s'affiche dans la boîte de dialogue."
 "export.progress.title": "Exportation"
@@ -483,6 +484,7 @@
 "project.context.reveal_in_finder": "Révéler dans le Finder"
 "project.context.replace_footage": "Remplacer les médias"
 "project.context.rename": "Renommer"
+"project.context.export_sequence": "Exporter la séquence…"
 "project.context.delete": "Supprimer"
 "project.context.open_in_new_tab": "Ouvrir dans un nouvel onglet"
 "project.context.open_in_new_window": "Ouvrir dans une nouvelle fenêtre"

assets/i18n/ja.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "プロジェクトファイルを書き出し…"
 "menu.file.save_as": "別名で保存…"
 "menu.file.revert": "保存済みに戻す"
-"menu.file.export_media": "メディアを書き出し…"
+"menu.file.export_media": "シーケンスを書き出し…"
 "menu.file.project_properties": "プロジェクトのプロパティ…"
 "menu.file.close": "プロジェクトを閉じる"
 "menu.file.quit": "終了"
@@ -389,6 +389,7 @@
 "project.export.format": "プロジェクト形式"
 "export.format.placeholder": "フォーマットを選択…"
 "export.path": "出力先"
+"export.sequence": "シーケンス"
 "export.run": "書き出し"
 "export.hint": "シーケンスはoaktaskの書き出しパスを通じて書き出されます。進捗はダイアログに表示されます。"
 "export.progress.title": "書き出し中"
@@ -483,6 +484,7 @@
 "project.context.reveal_in_finder": "Finderに表示"
 "project.context.replace_footage": "素材を置き換え"
 "project.context.rename": "名前を変更"
+"project.context.export_sequence": "シーケンスを書き出し…"
 "project.context.delete": "削除"
 "project.context.open_in_new_tab": "新しいタブで開く"
 "project.context.open_in_new_window": "新しいウィンドウで開く"

assets/i18n/pt.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "Exportar arquivo de projeto…"
 "menu.file.save_as": "Salvar como…"
 "menu.file.revert": "Reverter"
-"menu.file.export_media": "Exportar mídia…"
+"menu.file.export_media": "Exportar sequência…"
 "menu.file.project_properties": "Propriedades do projeto…"
 "menu.file.close": "Fechar projeto"
 "menu.file.quit": "Sair"
@@ -389,6 +389,7 @@
 "project.export.format": "Formato do projeto"
 "export.format.placeholder": "Selecionar um formato…"
 "export.path": "Caminho de saída"
+"export.sequence": "Sequência"
 "export.run": "Exportar"
 "export.hint": "A sequência é exportada pelo caminho de exportação do oaktask; o progresso é exibido no diálogo."
 "export.progress.title": "Exportando"
@@ -483,6 +484,7 @@
 "project.context.reveal_in_finder": "Revelar no Finder"
 "project.context.replace_footage": "Substituir mídia"
 "project.context.rename": "Renomear"
+"project.context.export_sequence": "Exportar sequência…"
 "project.context.delete": "Excluir"
 "project.context.open_in_new_tab": "Abrir em nova guia"
 "project.context.open_in_new_window": "Abrir em nova janela"

assets/i18n/ru.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "Экспортировать файл проекта…"
 "menu.file.save_as": "Сохранить как…"
 "menu.file.revert": "Восстановить"
-"menu.file.export_media": "Экспортировать медиафайлы…"
+"menu.file.export_media": "Экспортировать секвенцию…"
 "menu.file.project_properties": "Свойства проекта…"
 "menu.file.close": "Закрыть проект"
 "menu.file.quit": "Выход"
@@ -389,6 +389,7 @@
 "project.export.format": "Формат проекта"
 "export.format.placeholder": "Выберите формат…"
 "export.path": "Путь вывода"
+"export.sequence": "Секвенция"
 "export.run": "Экспортировать"
 "export.hint": "Последовательность экспортируется через путь экспорта oaktask; ход выполнения отображается в диалоговом окне."
 "export.progress.title": "Экспорт"
@@ -483,6 +484,7 @@
 "project.context.reveal_in_finder": "Показать в Finder"
 "project.context.replace_footage": "Заменить медиафайлы"
 "project.context.rename": "Переименовать"
+"project.context.export_sequence": "Экспортировать секвенцию…"
 "project.context.delete": "Удалить"
 "project.context.open_in_new_tab": "Открыть в новой вкладке"
 "project.context.open_in_new_window": "Открыть в новом окне"

assets/i18n/zh-CN.yaml

@@ -22,7 +22,7 @@
 "menu.file.export_project": "导出工程文件…"
 "menu.file.save_as": "另存为…"
 "menu.file.revert": "还原"
-"menu.file.export_media": "导出媒体…"
+"menu.file.export_media": "导出序列…"
 "menu.file.project_properties": "项目属性…"
 "menu.file.close": "关闭项目"
 "menu.file.quit": "退出"
@@ -387,6 +387,7 @@
 "project.export.format": "项目格式"
 "export.format.placeholder": "选择格式…"
 "export.path": "输出路径"
+"export.sequence": "序列"
 "export.run": "导出"
 "export.hint": "序列通过 oaktask 导出路径导出；进度显示在对话框中。"
 "export.progress.title": "正在导出"
@@ -481,6 +482,7 @@
 "project.context.reveal_in_finder": "在 Finder 中显示"
 "project.context.replace_footage": "替换素材"
 "project.context.rename": "重命名"
+"project.context.export_sequence": "导出序列…"
 "project.context.delete": "删除"
 "project.context.open_in_new_tab": "在新标签页中打开"
 "project.context.open_in_new_window": "在新窗口中打开"