release: v0.1.14 — syntax highlight, Mermaid, fileSystem, preview links

feat(core): syntax highlight editor overlay
- Transparent highlight-layer behind textarea with regex-based token coloring
- Supports heading, bold, italic, strikethrough, code, link, image, list, quote, hr
- Scroll-synced with textarea, config.syntaxHighlight toggle

feat(core): preview link click interception
- Clicks on preview links intercepted, emitted as 'linkClick' event
- Configurable via onLinkClick(uri, text, editor) callback
- Default: opens in new tab, anchor links pass through

feat(parser): Mermaid diagram rendering
- ```mermaid code blocks render as <div class="me-mermaid"><pre class="mermaid">

feat(plugins): fileSystem plugin (IndexedDB persistence)
- saveToFile(id) / loadFromFile(id) / deleteFile(id) / listFiles()
- Uses IndexedDB 'metona-editor-fs' database

feat(config): maxLength (char limit), syntaxHighlight toggle

style: syntax highlight theme colors, Mermaid container

chore: bump version 0.1.13 → 0.1.14 across all files

src/themes.js

@@ -1,7 +1,7 @@
 /**
  * MetonaEditor Themes — 主题系统（增强版）
  * @module themes
- * @version 0.1.13
+ * @version 0.1.14
  * @description 全局+实例级主题管理、CSS 变量隔离、外部主题跟随、主题继承
  *
  * v0.1.5 增强：