Move settings into a standalone Settings window

The tab-bar popover had outgrown itself. Settings now open in their own
native window (a fourth window kind, built like the connection manager but
not modal): a sidebar with Appearance, Transfers, Editor, File list and
About, holding every popover row plus the visible-columns choice. Each
control is an ordinary settings save, so the other windows follow live
while it stays open.

The gear button in the tab bar, Ctrl+, and the macOS app menu's
"Settings..." (Cmd+,) open it. On macOS Cmd+W arrives as the main window's
close-tab menu action, so bun closes the focused Settings window first
instead of a main-window tab.

Co-Authored-By: Claude <noreply@anthropic.com>

src/bun/index.ts

@@ -10,6 +10,7 @@ import { ManagerWindow } from "./manager-window";
 import { setLocale as setBackendLocale } from "./i18n";
 import { applyApplicationMenu } from "./menu";
 import { createAppRPC } from "./rpc-handlers";
+import { SettingsWindow } from "./settings-window";
 import { ConnectionStore } from "./store/connections";
 import { migrateLegacyDataDir } from "./store/paths";
 import { SettingsStore } from "./store/settings";
@@ -52,6 +53,7 @@ const events = {
 	openEditor: (_ctx: EditorOpenContext) => {},
 	settingsChanged: (_settings: AppSettings) => {},
 	openConnectionManager: () => {},
+	openSettings: () => {},
 	showAbout: () => {},
 };
 const rpc = createAppRPC({ registry, engine, store, settings, edits, watcher, events });
@@ -108,29 +110,43 @@ const manager = new ManagerWindow({
 	rebuildMenu: () => void applyApplicationMenu(store),
 	onSettingsSaved: (s) => settingsSaved(s, "manager"),
 });
+const settingsWin = new SettingsWindow({
+	settings,
+	url,
+	currentSettings: () => currentSettings,
+	mainFrame: () => win.getFrame(),
+	onSettingsSaved: (s) => settingsSaved(s, "settings"),
+	showAbout: () => showAbout(),
+});
 
 events.openEditor = (ctx) => editors.open(ctx);
 /**
  * Every settings save lands here, whichever window made it (editor and manager
- * windows save too — the scale shortcuts): side effects run once, then every
- * OTHER window follows. The sender is skipped — it already shows the new
- * values, and an echo arriving behind a newer local change (a held Cmd+) would
- * drag it backwards.
+ * windows save too — the scale shortcuts — and the Settings window is nothing
+ * but saves): side effects run once, then every OTHER window follows. The
+ * sender is skipped — it already shows the new values, and an echo arriving
+ * behind a newer local change (a held Cmd+) would drag it backwards.
  */
-function settingsSaved(s: AppSettings, sender: "main" | "manager" | { editor: string }): void {
+function settingsSaved(
+	s: AppSettings,
+	sender: "main" | "manager" | "settings" | { editor: string },
+): void {
 	engine.setConcurrency(effectiveConcurrency(s));
 	const localeChanged = s.locale !== currentSettings.locale;
 	currentSettings = s; // future windows' preloads bake the fresh theme
 	if (localeChanged) {
 		setBackendLocale(s.locale);
 		void applyApplicationMenu(store); // relabel the native menu in the new language
+		settingsWin.retitle();
 	}
 	if (sender !== "main") rpc.send.settingsChanged({ settings: s });
 	if (sender !== "manager") manager.broadcastSettings(s);
+	if (sender !== "settings") settingsWin.broadcastSettings(s);
 	editors.broadcastSettings(s, typeof sender === "object" ? sender.editor : undefined);
 }
 events.settingsChanged = (s) => settingsSaved(s, "main");
 events.openConnectionManager = () => manager.open();
+events.openSettings = () => settingsWin.open();
 
 function showAbout(): void {
 	const { build } = BRANDING;
@@ -149,6 +165,7 @@ events.showAbout = showAbout;
 // and the modal manager has nothing to guard
 win.on("close", () => {
 	manager.close();
+	settingsWin.close();
 	editors.closeAllForAppExit();
 });
 
@@ -173,6 +190,7 @@ engine.onUpdate = (snapshot) => {
 		if (
 			!windowFocused &&
 			!editors.anyFocused() &&
+			!settingsWin.isFocused() &&
 			(snapshot.state === "completed" || snapshot.state === "failed")
 		) {
 			Utils.showNotification({
@@ -230,10 +248,14 @@ void applyApplicationMenu(store);
 ApplicationMenu.on("application-menu-clicked", (event) => {
 	const action = (event as { data?: { action?: string } }).data?.action;
 	if (!action) return;
-	// ⌘W while an editor window is focused closes that editor (with its dirty
-	// prompt), not a main-window tab. Other menu actions deliberately still
-	// target the main window.
+	// ⌘W while the Settings window or an editor window is focused closes THAT
+	// window (an editor with its dirty prompt), not a main-window tab. Other
+	// menu actions deliberately still target the main window.
 	if (action === "close-tab") {
+		if (settingsWin.isFocused()) {
+			settingsWin.close();
+			return;
+		}
 		const focusedEditor = editors.focusedKey();
 		if (focusedEditor) {
 			editors.requestClose(focusedEditor);
@@ -244,6 +266,10 @@ ApplicationMenu.on("application-menu-clicked", (event) => {
 		manager.open();
 		return;
 	}
+	if (action === "settings") {
+		settingsWin.open();
+		return;
+	}
 	if (action === "about") {
 		showAbout();
 		return;