app: about dialog, modal close affordances, more preferences

- Help > About Oak… opens a real dialog (was a placeholder print): name
  + version, the GPL-3.0 line, the Olive fork notice and the thanks to
  Enzo GD (Community Promoter).
- Modal (gpui_widgets, submodule bump): a title-row close button on
  every dialog and opt-in backdrop dismissal (dismiss_on_mask) — Help >
  Search Actions and About use it, so they close on an outside click
  (previously a buttonless modal could only be closed with Escape).
- Preferences general tab grows two live settings: the cache-ahead
  pre-render window (PlaybackPreRenderFrames, consumed by the preview
  scheduler every playback tick) and the library storage backend
  (Storage/Backend sqlite/pg + Storage/PgUrl connection string, read by
  oak-storage's write-through when a project binds; the pg URL field
  shows only for PostgreSQL and commits on dialog close). The C++
  auto-recovery toggle is skipped on purpose: the Rust snapshot loop
  has no disable semantic, so the switch would be dead.

i18n keys for all eight packs; new tests cover the about modal and the
preferences writes.

assets/i18n/de.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "Standardort verwenden"
 "projprops.cache.alongside": "Zusammen mit dem Projekt speichern"
 "projprops.cache.custom": "Benutzerdefinierten Speicherort verwenden:"
+"about.title": "Über Oak"
+"about.description": "Oak Video Editor ist ein freier, quelloffener nichtlinearer Videoeditor. Diese Software ist unter der GNU GPL Version 3 lizenziert."
+"about.thanks": "Besonderer Dank gilt Enzo GD, unserem Community Promoter, für seine großzügige Unterstützung bei der Verbreitung dieses Projekts in dessen Anfangszeit."
+"about.fork_notice": "Dieses Projekt ist ein Fork des Olive Video Editors."
 "file.open.title": "Projekt öffnen"
 "file.import_footage.title": "Material importieren"
 "preferences.title": "Einstellungen"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "Verzeichnis für den Platten-Cache"
 "preferences.cache.browse": "Durchsuchen…"
+"preferences.cache.ahead": "Vorauspuffer (Frames)"
+"preferences.section.storage": "Speicher"
+"preferences.storage.backend": "Backend des Projektarchivs"
+"preferences.storage.pg_url": "PostgreSQL-Verbindungszeichenfolge"
+"preferences.storage.restart_hint": "Änderungen am Speicher-Backend gelten für Projekte, die anschließend geöffnet werden (ein Neustart wird empfohlen)."
 "preferences.proxy.enable": "Proxy-Medien verwenden"
 "preferences.proxy.resolution": "Proxy-Auflösung"
 "preferences.proxy.full": "Volle Auflösung"

assets/i18n/en-US.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "Use Default Location"
 "projprops.cache.alongside": "Store Alongside Project"
 "projprops.cache.custom": "Use Custom Location:"
+"about.title": "About Oak"
+"about.description": "Oak Video Editor is a free open source non-linear video editor. This software is licensed under the GNU GPL Version 3."
+"about.thanks": "Special thanks to Enzo GD, our Community Promoter, for his generous support in spreading the word about this project in its early days."
+"about.fork_notice": "This project is a fork of Olive Video Editor."
 "file.open.title": "Open Project"
 "file.import_footage.title": "Import Footage"
 "preferences.title": "Preferences"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "Disk cache directory"
 "preferences.cache.browse": "Browse…"
+"preferences.cache.ahead": "Cache ahead (frames)"
+"preferences.section.storage": "Storage"
+"preferences.storage.backend": "Library storage backend"
+"preferences.storage.pg_url": "PostgreSQL connection string"
+"preferences.storage.restart_hint": "Storage backend changes apply to projects opened afterwards (a restart is recommended)."
 "preferences.proxy.enable": "Use proxy media"
 "preferences.proxy.resolution": "Proxy resolution"
 "preferences.proxy.full": "Full resolution"

assets/i18n/es.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "Usar ubicación predeterminada"
 "projprops.cache.alongside": "Almacenar junto al proyecto"
 "projprops.cache.custom": "Usar ubicación personalizada:"
+"about.title": "Acerca de Oak"
+"about.description": "Oak Video Editor es un editor de vídeo no lineal libre y de código abierto. Este software está licenciado bajo la GNU GPL versión 3."
+"about.thanks": "Un agradecimiento especial a Enzo GD, nuestro Community Promoter, por su generoso apoyo al difundir este proyecto en sus primeros días."
+"about.fork_notice": "Este proyecto es un fork de Olive Video Editor."
 "file.open.title": "Abrir proyecto"
 "file.import_footage.title": "Importar material"
 "preferences.title": "Preferencias"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "Directorio de caché en disco"
 "preferences.cache.browse": "Examinar…"
+"preferences.cache.ahead": "Búfer anticipado (fotogramas)"
+"preferences.section.storage": "Almacenamiento"
+"preferences.storage.backend": "Backend de almacenamiento de la biblioteca"
+"preferences.storage.pg_url": "Cadena de conexión de PostgreSQL"
+"preferences.storage.restart_hint": "Los cambios del backend de almacenamiento se aplican a los proyectos abiertos después del cambio (se recomienda reiniciar)."
 "preferences.proxy.enable": "Usar medios proxy"
 "preferences.proxy.resolution": "Resolución del proxy"
 "preferences.proxy.full": "Resolución completa"

assets/i18n/fr.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "Utiliser l'emplacement par défaut"
 "projprops.cache.alongside": "Stocker à côté du projet"
 "projprops.cache.custom": "Utiliser un emplacement personnalisé :"
+"about.title": "À propos d'Oak"
+"about.description": "Oak Video Editor est un éditeur vidéo non linéaire libre et open source. Ce logiciel est sous licence GNU GPL version 3."
+"about.thanks": "Remerciements particuliers à Enzo GD, notre Community Promoter, pour son généreux soutien à la diffusion de ce projet à ses débuts."
+"about.fork_notice": "Ce projet est un fork d'Olive Video Editor."
 "file.open.title": "Ouvrir le projet"
 "file.import_footage.title": "Importer des médias"
 "preferences.title": "Préférences"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "Dossier du cache disque"
 "preferences.cache.browse": "Parcourir…"
+"preferences.cache.ahead": "Préchargement (images)"
+"preferences.section.storage": "Stockage"
+"preferences.storage.backend": "Backend de stockage de la bibliothèque"
+"preferences.storage.pg_url": "Chaîne de connexion PostgreSQL"
+"preferences.storage.restart_hint": "Les changements de backend de stockage s'appliquent aux projets ouverts après la modification (un redémarrage est recommandé)."
 "preferences.proxy.enable": "Utiliser les médias proxy"
 "preferences.proxy.resolution": "Résolution du proxy"
 "preferences.proxy.full": "Pleine résolution"

assets/i18n/ja.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "デフォルトの場所を使用"
 "projprops.cache.alongside": "プロジェクトと同じ場所に保存"
 "projprops.cache.custom": "カスタムの場所を使用："
+"about.title": "Oak について"
+"about.description": "Oak Video Editor はフリーでオープンソースのノンリニア動画エディタです。本ソフトウェアは GNU GPL バージョン 3 でライセンスされています。"
+"about.thanks": "プロジェクト初期に広く紹介してくれたコミュニティプロモーター Enzo GD に心より感謝します。"
+"about.fork_notice": "本プロジェクトは Olive Video Editor のフォークです。"
 "file.open.title": "プロジェクトを開く"
 "file.import_footage.title": "素材を読み込み"
 "preferences.title": "環境設定"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "ディスクキャッシュの保存先"
 "preferences.cache.browse": "参照…"
+"preferences.cache.ahead": "先読みキャッシュ（フレーム）"
+"preferences.section.storage": "ストレージ"
+"preferences.storage.backend": "ライブラリのストレージバックエンド"
+"preferences.storage.pg_url": "PostgreSQL接続文字列"
+"preferences.storage.restart_hint": "ストレージバックエンドの変更は、変更後に開いたプロジェクトに適用されます（再起動を推奨）。"
 "preferences.proxy.enable": "プロキシメディアを使用"
 "preferences.proxy.resolution": "プロキシ解像度"
 "preferences.proxy.full": "フル解像度"

assets/i18n/pt.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "Usar localização padrão"
 "projprops.cache.alongside": "Armazenar junto ao projeto"
 "projprops.cache.custom": "Usar localização personalizada:"
+"about.title": "Sobre o Oak"
+"about.description": "O Oak Video Editor é um editor de vídeo não linear livre e de código aberto. Este software é licenciado sob a GNU GPL versão 3."
+"about.thanks": "Um agradecimento especial a Enzo GD, nosso Community Promoter, por seu generoso apoio na divulgação deste projeto em seus primórdios."
+"about.fork_notice": "Este projeto é um fork do Olive Video Editor."
 "file.open.title": "Abrir projeto"
 "file.import_footage.title": "Importar mídia"
 "preferences.title": "Preferências"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "Diretório do cache em disco"
 "preferences.cache.browse": "Procurar…"
+"preferences.cache.ahead": "Pré-busca (quadros)"
+"preferences.section.storage": "Armazenamento"
+"preferences.storage.backend": "Backend de armazenamento da biblioteca"
+"preferences.storage.pg_url": "String de conexão do PostgreSQL"
+"preferences.storage.restart_hint": "As alterações do backend de armazenamento valem para projetos abertos depois da mudança (é recomendável reiniciar)."
 "preferences.proxy.enable": "Usar mídia proxy"
 "preferences.proxy.resolution": "Resolução do proxy"
 "preferences.proxy.full": "Resolução completa"

assets/i18n/ru.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "Использовать расположение по умолчанию"
 "projprops.cache.alongside": "Хранить рядом с проектом"
 "projprops.cache.custom": "Использовать пользовательское расположение:"
+"about.title": "О программе Oak"
+"about.description": "Oak Video Editor — свободный нелинейный видеоредактор с открытым исходным кодом. Программа распространяется по лицензии GNU GPL версии 3."
+"about.thanks": "Особая благодарность Enzo GD, нашему Community Promoter, за щедрую поддержку в распространении этого проекта в первые дни."
+"about.fork_notice": "Этот проект является форком Olive Video Editor."
 "file.open.title": "Открыть проект"
 "file.import_footage.title": "Импорт медиафайлов"
 "preferences.title": "Настройки"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "Каталог дискового кэша"
 "preferences.cache.browse": "Обзор…"
+"preferences.cache.ahead": "Упреждающий кэш (кадры)"
+"preferences.section.storage": "Хранилище"
+"preferences.storage.backend": "Бэкенд хранилища библиотеки"
+"preferences.storage.pg_url": "Строка подключения PostgreSQL"
+"preferences.storage.restart_hint": "Изменения бэкенда хранилища применяются к проектам, открытым после изменения (рекомендуется перезапуск)."
 "preferences.proxy.enable": "Использовать прокси-медиа"
 "preferences.proxy.resolution": "Разрешение прокси"
 "preferences.proxy.full": "Полное разрешение"

assets/i18n/zh-CN.yaml

@@ -247,6 +247,10 @@
 "projprops.cache.default": "使用默认位置"
 "projprops.cache.alongside": "随工程文件存储"
 "projprops.cache.custom": "使用自定义位置："
+"about.title": "关于 Oak"
+"about.description": "Oak 视频编辑器是一款自由开源的非线性视频编辑器。本软件以 GNU GPL 第三版许可证发布。"
+"about.thanks": "特别感谢我们的社区推广者 Enzo GD，感谢他在项目早期为传播本项目所给予的慷慨支持。"
+"about.fork_notice": "本项目是 Olive 视频编辑器的 fork。"
 "file.open.title": "打开项目"
 "file.import_footage.title": "导入素材"
 "preferences.title": "偏好设置"
@@ -271,6 +275,11 @@
 "preferences.theme.light": "Olive Light"
 "preferences.cache.dir": "磁盘缓存目录"
 "preferences.cache.browse": "浏览…"
+"preferences.cache.ahead": "缓存提前量（帧）"
+"preferences.section.storage": "存储"
+"preferences.storage.backend": "素材库存储后端"
+"preferences.storage.pg_url": "PostgreSQL 连接串"
+"preferences.storage.restart_hint": "存储后端更改在之后打开的项目上生效（建议重启）。"
 "preferences.proxy.enable": "使用代理媒体"
 "preferences.proxy.resolution": "代理分辨率"
 "preferences.proxy.full": "原始分辨率"

crates/oak-app/src/app.rs

@@ -121,6 +121,8 @@ mod modal_ids {
 	pub const PLUGIN_PROGRESS: usize = 10;
 	/// The action search dialog (Help > Search Actions…, the `/` key).
 	pub const ACTION_SEARCH: usize = 11;
+	/// The about dialog (Help > About Oak…).
+	pub const ABOUT: usize = 13;
 	/// The project properties dialog (File > Project Properties…).
 	pub const PROJECT_PROPERTIES: usize = 12;
 }
@@ -187,6 +189,8 @@ enum ModalState<E: AppEngine> {
 		modal: Entity<Modal>,
 		content: Entity<crate::dialogs::ProjectPropertiesContent<E>>,
 	},
+	/// The about dialog (Help > About Oak…; static content).
+	About { modal: Entity<Modal> },
 }
 
 /// A running export: the session the tick loop drains for progress.
@@ -207,7 +211,8 @@ impl<E: AppEngine> ModalState<E> {
 			| ModalState::ManagerDelete { modal, .. }
 			| ModalState::Proxy { modal, .. }
 			| ModalState::ActionSearch { modal, .. }
-			| ModalState::ProjectProperties { modal, .. } => Some(modal.clone()),
+			| ModalState::ProjectProperties { modal, .. }
+			| ModalState::About { modal } => Some(modal.clone()),
 		}
 	}
 }
@@ -1080,6 +1085,7 @@ impl<E: AppEngine> OakApp<E> {
 			| A::MulticamSwitchNoSplit9 => {}
 			// --- Help --------------------------------------------------------
 			A::ActionSearch => self.open_action_search(cx),
+			A::About => self.open_about(cx),
 			// --- everything else is a placeholder --------------------------
 			other => println!(
 				"[action] {} not wired yet (placeholder)",
@@ -1927,7 +1933,10 @@ impl<E: AppEngine> OakApp<E> {
 			let modal = app.new(|cx| {
 				Modal::new(
 					modal_ids::ACTION_SEARCH,
-					ModalOptions::new(crate::i18n::tr("menu.help.action_search"), px(640.0)),
+					ModalOptions::new(crate::i18n::tr("menu.help.action_search"), px(640.0))
+						// Launcher-style: a backdrop click dismisses (same as
+						// Escape and the title-row ✕).
+						.with_dismiss_on_mask(true),
 					window,
 					cx,
 				)
@@ -1959,6 +1968,30 @@ impl<E: AppEngine> OakApp<E> {
 		}
 	}
 
+	/// Opens the about dialog (Help > About Oak…): the app name, version,
+	/// license line and fork notice. No engine interaction.
+	fn open_about(&mut self, cx: &mut Context<Self>) {
+		if !matches!(self.modal, ModalState::None) {
+			return;
+		}
+		self.spawn_modal(cx, |window, app| {
+			let content = app.new(|_cx| crate::dialogs::AboutContent::new());
+			let modal = app.new(|cx| {
+				Modal::new(
+					modal_ids::ABOUT,
+					ModalOptions::new(crate::i18n::tr("about.title"), px(480.0))
+						.with_button(DialogButton::primary(crate::i18n::tr("dialog.ok")))
+						// Launcher-style dismissal is natural here too.
+						.with_dismiss_on_mask(true),
+					window,
+					cx,
+				)
+				.with_content(content.clone())
+			});
+			ModalState::About { modal }
+		});
+	}
+
 	/// Opens the proxy settings dialog (Tools > Proxy Settings; the C++
 	/// `ProxyDialog`): the global generation settings plus the footage
 	/// proxy list with Generate / Delete buttons.
@@ -2225,6 +2258,7 @@ impl<E: AppEngine> OakApp<E> {
 						}
 					}
 				}
+				modal_ids::ABOUT => self.close_modal(cx),
 				modal_ids::PROJECT_PROPERTIES => {
 					if let ModalState::ProjectProperties { content, .. } = &self.modal {
 						let content = content.clone();
@@ -3158,6 +3192,103 @@ mod tests {
 		);
 	}
 
+	/// The General tab's new rows are live end to end: the cache-ahead spin
+	/// box writes `PlaybackPreRenderFrames` (the playback pre-render window
+	/// reads it every tick) and the storage backend combo writes
+	/// `Storage/Backend` — PostgreSQL reveals the `Storage/PgUrl` field the
+	/// write-through library consumes.
+	#[gpui::test]
+	async fn preferences_general_tab_writes_cache_ahead_and_storage(cx: &mut TestAppContext) {
+		let _guard = crate::actions::shortcuts_test_lock()
+			.lock()
+			.unwrap_or_else(|e| e.into_inner());
+		let _lang = crate::i18n::lang_test_lock()
+			.lock()
+			.unwrap_or_else(|e| e.into_inner());
+		crate::i18n::set_language_code("en-US");
+
+		// The config store is process-wide: pin the keys to a known state and
+		// restore them afterwards so no other test inherits these writes.
+		struct Restore(&'static str, String);
+		impl Drop for Restore {
+			fn drop(&mut self) {
+				crate::oakui::real::config_set_string(self.0, &self.1);
+			}
+		}
+		let _ahead = Restore(
+			"PlaybackPreRenderFrames",
+			crate::oakui::real::config_get_string("PlaybackPreRenderFrames"),
+		);
+		let _backend = Restore(
+			"Storage/Backend",
+			crate::oakui::real::config_get_string("Storage/Backend"),
+		);
+		let _pg_url = Restore(
+			"Storage/PgUrl",
+			crate::oakui::real::config_get_string("Storage/PgUrl"),
+		);
+		crate::oakui::real::config_set_int("PlaybackPreRenderFrames", 120);
+		crate::oakui::real::config_set_string("Storage/Backend", "sqlite");
+
+		let (window, root) = mock_shell(cx);
+		cx.update(|app| root.update(app, |app, cx| app.on_menu(menu_ids::PREFERENCES, cx)));
+		cx.run_until_parked();
+		cx.update_window(window.into(), |_root, window, cx| {
+			window.draw(cx).clear();
+		})
+		.expect("window is still open");
+		cx.run_until_parked();
+		// Clear the app keymap: the global up/down/home/end bindings
+		// (GoToPrevCut / GoToNextCut / GoToStart / GoToEnd) dispatch before
+		// the controls' element key handlers and would shadow the spin
+		// box's arrow keys and the combo's selection keys.
+		cx.update(|cx| cx.clear_key_bindings());
+
+		let mut cx = VisualTestContext::from_window(window.into(), cx).into_mut();
+		// The connection-string row only exists for the PostgreSQL backend.
+		assert!(
+			cx.debug_bounds("preferences-storage-pg-url").is_none(),
+			"the PostgreSQL connection-string row is hidden for SQLite"
+		);
+
+		// Step the cache-ahead spin box once (8 frames): 120 → 128 lands in
+		// the config the playback pre-render window reads.
+		let ahead = cx
+			.debug_bounds("preferences-cache-ahead")
+			.expect("the cache-ahead row is rendered");
+		cx.simulate_click(ahead.center(), gpui::Modifiers::none());
+		cx.run_until_parked();
+		cx.dispatch_keystroke(window.into(), gpui::Keystroke::parse("up").unwrap());
+		cx.run_until_parked();
+		assert_eq!(
+			crate::oakui::real::config_get_int("PlaybackPreRenderFrames", 120),
+			128,
+			"the cache-ahead spin box writes its stepped value to the config"
+		);
+
+		// Re-select the storage backend: PostgreSQL (the combo starts on
+		// SQLite; with the popup closed the arrow keys drive the selection).
+		let backend = cx
+			.debug_bounds("preferences-storage-backend")
+			.expect("the storage backend row is rendered");
+		cx.simulate_click(backend.center(), gpui::Modifiers::none());
+		cx.run_until_parked();
+		cx.dispatch_keystroke(window.into(), gpui::Keystroke::parse("escape").unwrap());
+		cx.run_until_parked();
+		cx.dispatch_keystroke(window.into(), gpui::Keystroke::parse("down").unwrap());
+		cx.run_until_parked();
+		assert_eq!(
+			crate::oakui::real::config_get_string("Storage/Backend"),
+			"pg",
+			"selecting PostgreSQL writes Storage/Backend to the config"
+		);
+		// A fresh draw reveals the connection-string row.
+		cx.update(|window, cx| window.draw(cx).clear());
+		cx.run_until_parked();
+		cx.debug_bounds("preferences-storage-pg-url")
+			.expect("the PostgreSQL connection-string row appears after the switch");
+	}
+
 	/// Opening File → Project Properties… must not crash: the content is
 	/// built with the engine and the modal is layered onto the shell (the
 	/// same deferred-build path as Preferences).

crates/oak-app/src/dialogs.rs

@@ -46,9 +46,11 @@ use crate::oakui::real::{
 	config_get_bool, config_get_int, config_get_string, config_set_bool, config_set_int,
 	config_set_string, encoding_formats, proxy_dividers, renderer_backends, set_audio_input_device,
 	set_audio_output_device, set_theme_dark, theme_is_dark, CONFIG_KEY_DEFAULT_TRANSITION_SEC,
-	CONFIG_KEY_DISK_CACHE_PATH, CONFIG_KEY_FFMPEG_PATH, CONFIG_KEY_PROXY_DIVIDER,
-	CONFIG_KEY_RENDERER_BACKEND, CONFIG_KEY_SNAPSHOT_INTERVAL_SEC, CONFIG_KEY_USE_PROXY,
-	DEFAULT_SNAPSHOT_INTERVAL_SEC, DEFAULT_TRANSITION_SEC, EXPORT_FORMAT_MP4,
+	CONFIG_KEY_DISK_CACHE_PATH, CONFIG_KEY_FFMPEG_PATH, CONFIG_KEY_PG_URL,
+	CONFIG_KEY_PREVIEW_WINDOW, CONFIG_KEY_PROXY_DIVIDER, CONFIG_KEY_RENDERER_BACKEND,
+	CONFIG_KEY_SNAPSHOT_INTERVAL_SEC, CONFIG_KEY_STORAGE_BACKEND, CONFIG_KEY_USE_PROXY,
+	DEFAULT_PREVIEW_WINDOW_FORWARD, DEFAULT_SNAPSHOT_INTERVAL_SEC, DEFAULT_TRANSITION_SEC,
+	EXPORT_FORMAT_MP4,
 };
 
 // ---------------------------------------------------------------------------
@@ -77,7 +79,12 @@ impl gpui::EventEmitter<PreferencesEvent> for PreferencesContent {}
 ///
 /// * **常规 General** — language, theme.
 /// * **渲染 Rendering** — the renderer backend.
-/// * **缓存 Cache** — the disk cache directory (`DiskCachePath`).
+/// * **缓存 Cache** — the disk cache directory (`DiskCachePath`) and the
+///   playback pre-render window (`PlaybackPreRenderFrames`, the "cache
+///   ahead" frames the preview scheduler fills during playback).
+/// * **存储 Storage** — the write-through library backend
+///   (`Storage/Backend`, SQLite / PostgreSQL) and the PostgreSQL
+///   connection string (`Storage/PgUrl`).
 /// * **代理 Proxy** — use proxy media (`UseProxyMedia`), proxy resolution
 ///   divider (`ProxyDivider`).
 /// * **项目 Project** — the snapshot interval (`Storage/SnapshotIntervalSec`,
@@ -94,6 +101,7 @@ pub struct PreferencesContent {
 	language: Entity<ComboBox>,
 	theme: Entity<ComboBox>,
 	cache_dir: Entity<PathField>,
+	cache_ahead: Entity<SpinBox>,
 	use_proxy: Entity<CheckBox>,
 	hw_decode: Entity<CheckBox>,
 	proxy_divider: Entity<ComboBox>,
@@ -103,6 +111,11 @@ pub struct PreferencesContent {
 	transition_length: Entity<SpinBox>,
 	audio_output: Entity<ComboBox>,
 	audio_input: Entity<ComboBox>,
+	storage_backend: Entity<ComboBox>,
+	storage_pg_url: Entity<PathField>,
+	/// Whether the write-through library uses PostgreSQL (drives the
+	/// visibility of the connection-string field).
+	storage_is_pg: bool,
 	/// The backend options, in display order.
 	backends: Vec<&'static str>,
 	/// The proxy divider options, in display order (1 = full resolution).
@@ -211,6 +224,33 @@ impl PreferencesContent {
 		let configured_cache = config_get_string(CONFIG_KEY_DISK_CACHE_PATH);
 		cache_dir.update(cx, |field, cx| field.set_path(configured_cache, cx));
 
+		// --- 缓存 Cache: the playback pre-render window (cache ahead) ------
+		// The number of frames the preview scheduler fills ahead of the
+		// playhead during playback (`PlaybackPreRenderFrames`, consumed by
+		// `update_preview_window` every playback tick — no restart needed).
+		let cache_ahead = cx.new(|cx| {
+			let current = config_get_int(
+				CONFIG_KEY_PREVIEW_WINDOW,
+				DEFAULT_PREVIEW_WINDOW_FORWARD,
+			)
+			.clamp(8, 1200);
+			SpinBox::new(
+				10,
+				SliderModel::new(ValueKind::Integer, 8.0, 1200.0, 8.0, current as f64),
+				window,
+				cx,
+			)
+		});
+		cx.subscribe(&cache_ahead, |_this, _spin, event: &SpinBoxEvent, cx| {
+			let value = match event {
+				SpinBoxEvent::ValueChanged { value, .. }
+				| SpinBoxEvent::EditCommitted { value, .. } => value.to_f64() as i64,
+			};
+			config_set_int(CONFIG_KEY_PREVIEW_WINDOW, value);
+			let _ = cx;
+		})
+		.detach();
+
 		// --- 代理 Proxy -----------------------------------------------------
 		let use_proxy = cx.new(|cx| {
 			CheckBox::new(
@@ -412,11 +452,50 @@ impl PreferencesContent {
 		})
 		.detach();
 
+		// --- 存储 Storage: the write-through library backend ----------------
+		// `Storage/Backend` + `Storage/PgUrl` are read by oakstorage's
+		// write-through when a project binds (per-project library session),
+		// so a change applies to projects opened afterwards.
+		let storage_is_pg = config_get_string(CONFIG_KEY_STORAGE_BACKEND) == "pg";
+		let storage_backend = cx.new(|cx| {
+			let options = vec![
+				ComboBoxOption::new(0, "SQLite"),
+				ComboBoxOption::new(1, "PostgreSQL"),
+			];
+			ComboBox::new(11, options, window, cx)
+		});
+		cx.subscribe(&storage_backend, |this, _combo, event: &ComboBoxEvent, cx| {
+			match *event {
+				ComboBoxEvent::Selected { value } => {
+					let backend = if value == 1 { "pg" } else { "sqlite" };
+					this.storage_is_pg = backend == "pg";
+					config_set_string(CONFIG_KEY_STORAGE_BACKEND, backend);
+					// Re-render so the connection-string row shows/hides with
+					// the selection.
+					cx.notify();
+				}
+			}
+		})
+		.detach();
+		storage_backend.update(cx, |combo, cx| {
+			combo.set_selected(Some(if storage_is_pg { 1 } else { 0 }), cx)
+		});
+		let storage_pg_url = cx.new(|cx| {
+			let editor = cx.new(|cx| EditableTextState::new(StringStorage::default(), cx));
+			PathField {
+				editor,
+				enabled: true,
+			}
+		});
+		let configured_pg_url = config_get_string(CONFIG_KEY_PG_URL);
+		storage_pg_url.update(cx, |field, cx| field.set_path(configured_pg_url, cx));
+
 		Self {
 			backend,
 			language,
 			theme,
 			cache_dir,
+			cache_ahead,
 			use_proxy,
 			hw_decode,
 			proxy_divider,
@@ -426,6 +505,9 @@ impl PreferencesContent {
 			transition_length,
 			audio_output,
 			audio_input,
+			storage_backend,
+			storage_pg_url,
+			storage_is_pg,
 			backends,
 			dividers,
 			output_devices,
@@ -440,6 +522,13 @@ impl PreferencesContent {
 		config_set_string(crate::oakui::displaycolor::CONFIG_KEY_CUSTOM_ICC, &path);
 	}
 
+	/// Commits the PostgreSQL connection-string field to the config (called
+	/// by the host when the dialog closes, like the cache directory).
+	pub fn commit_storage_pg_url(&self, cx: &App) {
+		let url = self.storage_pg_url.read(cx).path(cx).trim().to_string();
+		config_set_string(CONFIG_KEY_PG_URL, &url);
+	}
+
 	/// Opens the platform file picker for a custom ICC profile.
 	fn browse_display_icc(&mut self, cx: &mut Context<Self>) {
 		let receiver = cx.prompt_for_paths(gpui::PathPromptOptions {
@@ -650,6 +739,43 @@ impl Render for PreferencesContent {
 							})),
 					),
 			))
+			// 缓存 Cache: cache ahead (playback pre-render window)
+			.child(form_row(
+				&colors,
+				i18n::tr("preferences.cache.ahead").into(),
+				div()
+					.debug_selector(|| "preferences-cache-ahead".into())
+					.child(self.cache_ahead.clone()),
+			))
+			// 存储 Storage
+			.child(section_header(
+				&colors,
+				i18n::tr("preferences.section.storage").into(),
+			))
+			.child(form_row(
+				&colors,
+				i18n::tr("preferences.storage.backend").into(),
+				div()
+					.debug_selector(|| "preferences-storage-backend".into())
+					.child(self.storage_backend.clone()),
+			))
+			.child(if self.storage_is_pg {
+				form_row(
+					&colors,
+					i18n::tr("preferences.storage.pg_url").into(),
+					div()
+						.debug_selector(|| "preferences-storage-pg-url".into())
+						.child(self.storage_pg_url.clone()),
+				)
+			} else {
+				div()
+			})
+			.child(
+				div()
+					.text_color(colors.disabled)
+					.text_xs()
+					.child(i18n::tr("preferences.storage.restart_hint")),
+			)
 			// 代理 Proxy
 			.child(section_header(
 				&colors,
@@ -1637,11 +1763,13 @@ impl PreferencesDialogContent {
 	}
 
 	/// Commits the general tab's free-text fields (the cache directory, the
-	/// custom ICC path), for the host when the dialog closes.
+	/// custom ICC path, the PostgreSQL connection string), for the host when
+	/// the dialog closes.
 	pub fn commit_cache_dir(&self, cx: &App) {
 		let general = self.general.read(cx);
 		general.commit_cache_dir(cx);
 		general.commit_display_icc_path(cx);
+		general.commit_storage_pg_url(cx);
 	}
 
 	/// The keyboard tab's action-row count (tests).
@@ -2558,6 +2686,54 @@ fn selection_step(visible: &[usize], current: Option<usize>, delta: i32) -> Opti
 	Some(visible[next])
 }
 
+// ---------------------------------------------------------------------------
+// About (帮助 → 关于 Oak)
+// ---------------------------------------------------------------------------
+
+/// The About dialog's content: the app name + version, the GPL-3.0 license
+/// line and the Olive fork notice (the C++ AboutDialog's text block; the
+/// patrons scroller is not ported).
+pub struct AboutContent;
+
+impl AboutContent {
+	/// Builds the static about text.
+	pub fn new() -> Self {
+		Self
+	}
+}
+
+impl Render for AboutContent {
+	fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
+		let colors = cx.default_colors().clone();
+		div()
+			.flex()
+			.flex_col()
+			.gap_2()
+			.child(
+				div()
+					.text_color(colors.text)
+					.font_weight(gpui::FontWeight::BOLD)
+					.child(format!("Oak Video Editor {}", env!("CARGO_PKG_VERSION"))),
+			)
+			.child(
+				div()
+					.text_color(colors.text)
+					.child(i18n::tr("about.description")),
+			)
+			.child(
+				div()
+					.text_color(colors.text)
+					.child(i18n::tr("about.thanks")),
+			)
+			.child(
+				div()
+					.text_color(colors.disabled)
+					.text_xs()
+					.child(i18n::tr("about.fork_notice")),
+			)
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;

crates/oak-app/src/oakui/real.rs

@@ -253,9 +253,9 @@ enum FullResTarget {
 // their slots back to the workers.
 
 /// The default forward pre-render window (frames).
-const DEFAULT_PREVIEW_WINDOW_FORWARD: i64 = 120;
+pub const DEFAULT_PREVIEW_WINDOW_FORWARD: i64 = 120;
 /// Config key for the forward pre-render window size (frames).
-const CONFIG_KEY_PREVIEW_WINDOW: &str = "PlaybackPreRenderFrames";
+pub const CONFIG_KEY_PREVIEW_WINDOW: &str = "PlaybackPreRenderFrames";
 
 /// One monitor's playback pre-render state (UI-thread-owned; the completions
 /// delivered by the dispatcher's poll run on the UI thread too).
@@ -5403,6 +5403,10 @@ pub fn audio_init_from_config() {
 /// The config key selecting the storage backend (see
 /// `crates/oakstorage/src/writethrough.rs`).
 pub const CONFIG_KEY_STORAGE_BACKEND: &str = "Storage/Backend";
+/// The config key holding the PostgreSQL connection string (`Storage/PgUrl`,
+/// `user:pass@host:5432/dbname`; used when the backend is `"pg"` — see
+/// `crates/oakstorage/src/writethrough.rs`).
+pub const CONFIG_KEY_PG_URL: &str = "Storage/PgUrl";
 
 /// Enables the SQLite write-through library unless the user configured the
 /// backend explicitly (any existing value — including "off" — wins over the