Toolbar button broken on non-English systems — actionName hardcoded to English

[renky25]

Bug Description

The toolbar Toggle Preview button doesn't work on non-English systems because actionName is hardcoded to "Change Mode", but MarkEdit-preview localizes menu item titles.

Root Cause

firstActionNamed in MarkEdit does an exact title match:

// MarkEditMac/Sources/Extensions/NSMenu+Extension.swift
func firstActionNamed(_ title: String) -> NSMenuItem? {
    firstDescendant {
      $0.title == title && $0.action != nil
    }
}

And MarkEdit-preview localizes the menu title per system language:

https://github.com/MarkEdit-app/MarkEdit-preview/blob/main/src/shared/strings.ts

'zh-CN':  { changeMode: '切换模式' },
'zh-TW':  { changeMode: '切換模式' },
'default': { changeMode: 'Change Mode' },

But Apply One-Click Toggle Setup always writes:

jsonc
"actionName": "Change Mode"   // ❌ only works on English systems

Steps to Reproduce

1. Set macOS system language to 简体中文 (zh-CN)
2. Install MarkEdit-preview + Direct Preview
3. Run "Apply One-Click Toggle Setup"
4. Restart MarkEdit, add the Toggle Preview toolbar button
5. Click the 👁 button → nothing happens

Expected Behavior

The toolbar button should toggle Edit ↔ Preview regardless of system language.

Suggested Fix

Instead of hardcoding English, there are a few options:

1. Simplest: Accept multiple actionName values and try them in order:
jsonc
"actionName": ["Change Mode", "切换模式", "切換模式"]
2. Robust: Read the localized string from MarkEdit-preview's settings.json or expose it via an API.
3. Workaround for users: Document in README that non-English users need to manually change actionName to match their locale.

Environment

- macOS 26 (Sequoia)
- MarkEdit 1.33+
- MarkEdit-preview v1.8.1
- Direct Preview v0.1.0
- System Language: zh-CN (简体中文)

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