feat: v0.2.1 — reference links, context menu, RTL, ja/ko, regex search, hooks, copy API

## Added
- Reference link/image resolution: [text][ref] + ![alt][ref] with [ref]: url definitions
- Right-click context menu: undo/redo/cut/copy/paste/selectAll + custom items
- RTL CSS layout support for Arabic, Hebrew, Persian etc.
- Japanese (ja) and Korean (ko) locales with 60+ keys each
- Divider position localStorage persistence
- Regex search toggle in search/replace panel
- Export HTML with embedded CSS styles
- beforeChange / afterChange lifecycle hooks (instance + global)
- copyAsMarkdown() / copyAsHTML() clipboard APIs
- CHANGELOG.md, CONTRIBUTING.md, CI workflow (.github/workflows/ci.yml)
- 2 new test suites: index.test.ts, styles.test.ts (684 total tests, +74)

## Changed
- autoSave plugin: closure-based state per instance instead of this context
- Plugin install() now receives options as second argument
- RTL locale detection: now uses language prefix (ar-SA → RTL)
- Rollup dev mode: only builds UMD format
- prepublishOnly now includes typecheck + test
- Version bumped to 0.2.1

## Fixed
- [text][ref] now correctly renders as link (was raw text)
- ![alt][ref] no longer produces empty src
- autoSave plugin state isolation across multiple editor instances
- Footnote definitions no longer consumed by refDef handler

src/i18n.ts

@@ -131,8 +131,9 @@ export const getLocaleName = (locale: string): string => {
 };
 
 export const getLocaleDirection = (locale: string): 'ltr' | 'rtl' => {
-  const rtlLocales = ['ar', 'he', 'fa', 'ur', 'yi', 'ps', 'sd', 'ug'];
-  return rtlLocales.includes(locale) ? 'rtl' : 'ltr';
+  const rtlLocales = ['ar', 'he', 'fa', 'ur', 'yi', 'ps', 'sd', 'ug', 'dv', 'ku', 'syr'];
+  const short = locale.split('-')[0].toLowerCase();
+  return rtlLocales.includes(short) ? 'rtl' : 'ltr';
 };
 
 export const formatNumber = (number: number, options: Intl.NumberFormatOptions = {}): string => {
@@ -262,6 +263,8 @@ export const createI18nManager = () => ({
 export const presetLocales = {
   'zh-CN': { name: '简体中文', nativeName: '简体中文', direction: 'ltr', translations: LOCALES['zh-CN'] },
   'en-US': { name: 'English (US)', nativeName: 'English (US)', direction: 'ltr', translations: LOCALES['en-US'] },
+  ja: { name: '日本語', nativeName: '日本語', direction: 'ltr', translations: (LOCALES as any)['ja'] },
+  ko: { name: '한국어', nativeName: '한국어', direction: 'ltr', translations: (LOCALES as any)['ko'] },
 };
 
 export const i18nUtils = createI18nManager();