release: v0.1.2 — readOnly, new syntax, plugins, optimizations

Features:
- feat(core): readOnly mode with config option and setReadOnly() API
- feat(parser): superscript ^text^ and subscript ~text~ support
- feat(parser): highlight/mark ==text== syntax
- feat(parser): table column alignment with colons (:---, :---:, ---:)
- feat(parser): emoji shortcodes 😄 → 😊 (80+ common emojis)
- feat(plugins): imagePaste preset — paste clipboard images as base64
- feat(core): instance-level beforeRender/afterRender events
- feat(styles): print stylesheet (@media print)
- feat(styles): mark element CSS styling
- feat(styles): readOnly mode CSS (.me-readonly)

Optimizations:
- perf(core): history debounce now configurable via historyDebounce option
- perf(core): skip _render() in edit-only mode (already guarded)
- fix(core): divider drag division-by-zero guard
- fix(core): config.style deep merge with DEFAULTS
- fix(core): scroll position preserved across mode switches

Tests:
- 9 new test cases: readOnly (3), parser syntax (6)
- Total: 418 tests passing (+9 from v0.1.1)

Chores:
- version bump 0.1.1 → 0.1.2
- TypeScript definitions updated for new APIs

src/core.js

@@ -1,7 +1,7 @@
 /**
  * MetonaEditor Core - 编辑器核心
  * @module core
- * @version 0.1.1
+ * @version 0.1.2
  * @description MarkdownEditor 类实现：DOM 构建、事件、渲染、历史栈、选区操作、模式切换
  */
 
@@ -74,7 +74,7 @@ class MarkdownEditor {
 
     this.config = { ...DEFAULTS, ...options };
     if (options.style && typeof options.style === 'object') {
-      this.config.style = { ...options.style };
+      this.config.style = { ...DEFAULTS.style, ...options.style };
     }
 
     this._value = this.config.value || '';
@@ -136,6 +136,7 @@ class MarkdownEditor {
   _buildDOM() {
     const wrapper = document.createElement('div');
     wrapper.className = `me-wrapper me-theme-${resolveThemeName(this.config.theme)}`;
+    if (this.config.readOnly) wrapper.classList.add('me-readonly');
     wrapper.dataset.id = this.id;
     wrapper.setAttribute('role', 'application');
     wrapper.setAttribute('aria-label', i18nT('edit'));
@@ -166,6 +167,7 @@ class MarkdownEditor {
     const textarea = document.createElement('textarea');
     textarea.className = 'me-textarea';
     textarea.spellcheck = !!this.config.spellcheck;
+    textarea.readOnly = !!this.config.readOnly;
     textarea.placeholder = this.config.placeholder || i18nT('placeholder');
     textarea.setAttribute('aria-label', i18nT('edit'));
     editorPane.appendChild(textarea);
@@ -410,6 +412,7 @@ class MarkdownEditor {
     const startX = e.clientX;
     const editorWidth = this.editorPane.getBoundingClientRect().width;
     const totalWidth = this.bodyEl.getBoundingClientRect().width;
+    if (totalWidth <= 0) return;
     const divider = this.dividerEl;
 
     const onMove = (ev) => {
@@ -443,6 +446,7 @@ class MarkdownEditor {
   _render() {
     if (this._mode === 'edit') return;
     MarkdownEditor.trigger('beforeRender', this);
+    this._emit('beforeRender', this);
 
     const env = {
       highlight: this._highlightFn,
@@ -463,13 +467,14 @@ class MarkdownEditor {
 
     this.previewEl.innerHTML = html;
     MarkdownEditor.trigger('afterRender', this);
+    this._emit('afterRender', this);
   }
 
   // ============ 历史栈 ============
 
   _scheduleHistory() {
     if (this._historyTimer) clearTimeout(this._historyTimer);
-    this._historyTimer = setTimeout(() => this._pushHistory(), 400);
+    this._historyTimer = setTimeout(() => this._pushHistory(), this.config.historyDebounce || 400);
   }
 
   _pushHistory() {
@@ -668,10 +673,16 @@ class MarkdownEditor {
 
   setMode(mode) {
     if (!MODES.includes(mode) || mode === this._mode) return this;
+    // 保存当前滚动位置
+    const taScroll = this.textarea ? this.textarea.scrollTop : 0;
+    const pvScroll = this.previewPane ? this.previewPane.scrollTop : 0;
     this._mode = mode;
     this.bodyEl.className = `me-body me-mode-${mode}`;
     this._updateModeButtons();
     if (mode !== 'edit') this._render();
+    // 恢复滚动位置
+    if (this.textarea) this.textarea.scrollTop = taScroll;
+    if (this.previewPane) this.previewPane.scrollTop = pvScroll;
     this._emit('modeChange', mode);
     if (typeof this.config.onModeChange === 'function') {
       try { this.config.onModeChange(mode, this); } catch (e) { console.error(e); }
@@ -816,6 +827,18 @@ class MarkdownEditor {
 
   isDisabled() { return this.textarea.disabled; }
 
+  /**
+   * 设置只读模式
+   */
+  setReadOnly(readOnly) {
+    this.config.readOnly = !!readOnly;
+    if (this.textarea) this.textarea.readOnly = !!readOnly;
+    if (this.el) this.el.classList.toggle('me-readonly', !!readOnly);
+    return this;
+  }
+
+  isReadOnly() { return this.config.readOnly; }
+
   /**
    * 注册实例事件监听
    * 支持事件：change/input/focus/blur/save/modeChange/fullscreen/beforeCreate/afterCreate/beforeRender/afterRender/destroy