feat(settings): expose the interactive terminal theme picker

Packages/macOS/CmuxSettingsUI/Sources/CmuxSettingsUI/Environment/SettingsHostActions.swift

@@ -68,6 +68,9 @@ public protocol SettingsHostActions: AnyObject {
     /// Live-reloads Ghostty after the adaptive-default-theme preference commits.
     func terminalAdaptiveDefaultThemeDidChange()
 
+    /// Opens the interactive terminal theme picker in a focused cmux terminal pane.
+    func openTerminalThemePicker()
+
     /// Launches the host's browser-import flow (Safari / Chrome /
     /// Firefox source picker + profile selection + cookie prompt).
     func openBrowserImportFlow()
@@ -364,6 +367,9 @@ public extension SettingsHostActions {
     /// Default no-op for package-only settings hosts without Ghostty.
     func terminalAdaptiveDefaultThemeDidChange() {}
 
+    /// Default no-op for package-only settings hosts without a terminal theme picker.
+    func openTerminalThemePicker() {}
+
     /// Default no-op for hosts with no app-owned reset side effects.
     func resetAllSettingsSideEffects() {}
 

Packages/macOS/CmuxSettingsUI/Sources/CmuxSettingsUI/Sections/TerminalSection.swift

@@ -257,6 +257,20 @@ public struct TerminalSection: View {
                 }
             }
             SettingsCardDivider()
+            SettingsCardRow(
+                configurationReview: .settingsOnly,
+                String(localized: "settings.app.theme", defaultValue: "Theme")
+            ) {
+                Button(
+                    String(localized: "settings.browser.import.choose", defaultValue: "Choose…")
+                ) {
+                    hostActions.openTerminalThemePicker()
+                }
+                .buttonStyle(.bordered)
+                .controlSize(.small)
+                .accessibilityIdentifier("SettingsTerminalThemePickerButton")
+            }
+            SettingsCardDivider()
             SettingsCardRow(
                 configurationReview: .json("terminal.adaptiveDefaultTheme"),
                 String(

Sources/HostSettingsActions.swift

@@ -8,7 +8,7 @@ import Foundation
 import OSLog
 import SwiftUI
 
-private let hostSettingsLogger = Logger(subsystem: "com.cmuxterm.app", category: "Settings")
+nonisolated private let hostSettingsLogger = Logger(subsystem: "com.cmuxterm.app", category: "Settings")
 
 /// App-side implementation of the package's `SettingsHostActions`
 /// protocol. Routes UI-triggered actions to the existing host
@@ -110,6 +110,44 @@ final class HostSettingsActions: SettingsHostActions {
         TerminalAdaptiveDefaultThemeSettings.notifyDidChange()
     }
 
+    func openTerminalThemePicker() {
+        let cliURL = Bundle.main.bundleURL
+            .appendingPathComponent("Contents/Resources/bin/cmux", isDirectory: false)
+        guard FileManager.default.isExecutableFile(atPath: cliURL.path) else {
+            hostSettingsLogger.error("Theme picker unavailable: bundled cmux CLI missing")
+            return
+        }
+
+        guard let appDelegate = AppDelegate.shared,
+              let manager = appDelegate.activeTabManagerForCommands(),
+              let workspace = manager.selectedWorkspace else {
+            NSSound.beep()
+            return
+        }
+
+        // The native Settings entry point keeps CLI diagnostics private. The
+        // interactive picker still owns stdout/the TTY, while raw helper and
+        // launch errors on stderr are suppressed on this user-facing path.
+        let initialCommand = "\(LocalSurfaceProvider.shellQuote(cliURL.path)) themes 2>/dev/null; exit"
+        do {
+            let picker = try SurfacePaneFactory.makeTerminalPane(
+                initialCommand: initialCommand,
+                workingDirectory: nil,
+                at: .workspace(id: workspace.id, placement: .tab),
+                focus: true
+            )
+            if let windowID = appDelegate.windowId(for: manager) {
+                _ = appDelegate.focusMainWindow(windowId: windowID)
+            }
+            SurfacePaneFactory.focus(
+                panelID: picker.panelID,
+                in: picker.workspaceID
+            )
+        } catch {
+            hostSettingsLogger.error("Failed to open terminal theme picker")
+        }
+    }
+
     func notifyShortcutSettingsDidChange() {
         // reload() already posts didChangeNotification when the file's
         // contents changed; posting again here double-notified every