release: v0.1.3 — bug fixes, performance, hardening

Bug Fixes:
- fix(core): exec() now supports _customActions registered via addToolbarButton
- fix(core): _emit('focus'/'blur') no longer passes editor argument twice
- fix(core): getHTML() now triggers beforeRender/afterRender hooks
- fix(core): _wrapSelection defaults to 'text' instead of i18n placeholder
- fix(core): addToolbarButton onClick+action no longer double-fires
- fix(core): null-safety on focus/blur/enable/disable after destroy
- fix(parser): empty headings (# ) no longer produce empty <h1> tags
- fix(parser): slugify returns 'heading' fallback for empty/special inputs
- fix(i18n): setCurrentLocale no longer mutates input parameter
- fix(core): autofocus skipped when readOnly is enabled

Performance:
- perf(core): cache last rendered value, skip parsing when content unchanged
- perf(core): add refresh() API to force re-render after theme/locale changes

Hardening:
- feat(core): tabSize dynamically applied to textarea via style.tabSize
- feat(core): getStatus() now includes readOnly field

Tests:
- 7 new test cases: customActions, refresh, focus args, destroy safety,
  getStatus readOnly, autofocus+readOnly, slugify edge cases
- Total: 425 tests passing (+7 from v0.1.2)

Types:
- EditorStatus includes readOnly field
- MarkdownEditor.refresh() added to type definitions

src/core.js

@@ -1,7 +1,7 @@
 /**
  * MetonaEditor Core - 编辑器核心
  * @module core
- * @version 0.1.2
+ * @version 0.1.3
  * @description MarkdownEditor 类实现：DOM 构建、事件、渲染、历史栈、选区操作、模式切换
  */
 
@@ -88,6 +88,7 @@ class MarkdownEditor {
     this._historyTimer = null;
     this._fullscreen = false;
     this._destroyed = false;
+    this._lastRenderedValue = null;
 
     // 渲染函数：自定义覆盖内置解析器
     this._renderFn = (typeof this.config.render === 'function') ? this.config.render : parseMarkdown;
@@ -122,7 +123,7 @@ class MarkdownEditor {
       this.config.plugins.forEach((p) => this.use(p));
     }
 
-    if (this.config.autofocus) this.focus();
+    if (this.config.autofocus && !this.config.readOnly) this.focus();
 
     if (typeof this.config.onCreate === 'function') {
       try { this.config.onCreate(this); } catch (e) { console.error('onCreate error:', e); }
@@ -168,6 +169,7 @@ class MarkdownEditor {
     textarea.className = 'me-textarea';
     textarea.spellcheck = !!this.config.spellcheck;
     textarea.readOnly = !!this.config.readOnly;
+    textarea.style.tabSize = String(this.config.tabSize || 2);
     textarea.placeholder = this.config.placeholder || i18nT('placeholder');
     textarea.setAttribute('aria-label', i18nT('edit'));
     editorPane.appendChild(textarea);
@@ -294,13 +296,13 @@ class MarkdownEditor {
     ta.addEventListener('scroll', onScroll);
 
     const onFocus = () => {
-      this._emit('focus', this);
+      this._emit('focus');
       if (typeof this.config.onFocus === 'function') {
         try { this.config.onFocus(this); } catch (e) { console.error(e); }
       }
     };
     const onBlur = () => {
-      this._emit('blur', this);
+      this._emit('blur');
       if (typeof this.config.onBlur === 'function') {
         try { this.config.onBlur(this); } catch (e) { console.error(e); }
       }
@@ -445,6 +447,9 @@ class MarkdownEditor {
 
   _render() {
     if (this._mode === 'edit') return;
+    // 内容未变化时跳过解析（主题切换等场景触发重渲染但内容不变）
+    if (this._lastRenderedValue === this._value) return;
+    this._lastRenderedValue = this._value;
     MarkdownEditor.trigger('beforeRender', this);
     this._emit('beforeRender', this);
 
@@ -544,7 +549,11 @@ class MarkdownEditor {
       fullscreen: () => this.toggleFullscreen(),
     };
     const fn = actions[action];
-    if (fn) fn.apply(this, args);
+    if (fn) { fn.apply(this, args); return this; }
+    // 检查自定义动作（通过 addToolbarButton 注册）
+    if (this._customActions && typeof this._customActions[action] === 'function') {
+      try { this._customActions[action].apply(this, args); } catch (e) { console.error('custom action error:', e); }
+    }
     return this;
   }
 
@@ -553,7 +562,7 @@ class MarkdownEditor {
     const start = ta.selectionStart;
     const end = ta.selectionEnd;
     const selected = ta.value.slice(start, end);
-    const text = selected || (i18nT('placeholder') || 'text');
+    const text = selected || 'text';
     const inserted = before + text + after;
 
     ta.value = ta.value.slice(0, start) + inserted + ta.value.slice(end);
@@ -776,14 +785,27 @@ class MarkdownEditor {
   }
 
   getHTML() {
+    MarkdownEditor.trigger('beforeRender', this);
+    this._emit('beforeRender', this);
     const env = { highlight: this._highlightFn, locale: getCurrentLocale() };
     let html = this._renderFn(this._value, env);
     if (typeof this.config.sanitize === 'function') {
       try { html = this.config.sanitize(html); } catch (e) { console.error(e); }
     }
+    MarkdownEditor.trigger('afterRender', this);
+    this._emit('afterRender', this);
     return html;
   }
 
+  /**
+   * 强制刷新预览（内容未变但需重渲染时使用，如主题切换）
+   */
+  refresh() {
+    this._lastRenderedValue = null;
+    this._render();
+    return this;
+  }
+
   insert(text, opts = {}) {
     const ta = this.textarea;
     const start = ta.selectionStart;
@@ -810,22 +832,22 @@ class MarkdownEditor {
     return this;
   }
 
-  focus() { this.textarea.focus(); return this; }
-  blur() { this.textarea.blur(); return this; }
+  focus() { if (this.textarea) this.textarea.focus(); return this; }
+  blur() { if (this.textarea) this.textarea.blur(); return this; }
 
   enable() {
-    this.textarea.disabled = false;
-    this.el.classList.remove('me-disabled');
+    if (this.textarea) this.textarea.disabled = false;
+    if (this.el) this.el.classList.remove('me-disabled');
     return this;
   }
 
   disable() {
-    this.textarea.disabled = true;
-    this.el.classList.add('me-disabled');
+    if (this.textarea) this.textarea.disabled = true;
+    if (this.el) this.el.classList.add('me-disabled');
     return this;
   }
 
-  isDisabled() { return this.textarea.disabled; }
+  isDisabled() { return this.textarea ? this.textarea.disabled : false; }
 
   /**
    * 设置只读模式
@@ -902,14 +924,14 @@ class MarkdownEditor {
     const btn = document.createElement('button');
     btn.type = 'button';
     btn.className = `me-btn me-btn-custom-${config.action}`;
-    btn.dataset.action = config.action;
     btn.title = config.title || config.action;
     btn.setAttribute('aria-label', config.title || config.action);
     btn.innerHTML = config.icon || `<span>${escapeHTML(config.text || config.action)}</span>`;
     if (typeof config.onClick === 'function') {
-      btn.addEventListener('click', () => config.onClick(this));
+      // 直接绑定 click，不设置 data-action 避免工具栏委托重复触发
+      btn.addEventListener('click', (e) => { e.stopPropagation(); config.onClick(this); });
     } else if (config.action) {
-      // 注册到 exec 动作
+      btn.dataset.action = config.action;
       this._customActions = this._customActions || {};
       this._customActions[config.action] = config.handler;
     }
@@ -969,6 +991,7 @@ class MarkdownEditor {
       theme: this.config.theme,
       locale: getCurrentLocale(),
       fullscreen: this._fullscreen,
+      readOnly: this.config.readOnly || false,
       disabled: this.textarea ? this.textarea.disabled : false,
       destroyed: this._destroyed,
       plugins: this._plugins.map((p) => p.name || 'custom'),