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/styles.js

@@ -1,7 +1,7 @@
 /**
  * MetonaEditor Styles - 编辑器样式
  * @module styles
- * @version 0.1.1
+ * @version 0.1.2
  * @description 编辑器 UI 样式注入与管理
  */
 
@@ -323,6 +323,34 @@ const generateCSS = () => {
     /* ============ 全屏模式优化 ============ */
     .me-wrapper.me-fullscreen .me-preview,
     .me-wrapper.me-fullscreen .me-textarea { font-size: 15px; }
+
+    /* ============ 只读模式 ============ */
+    .me-wrapper.me-readonly .me-textarea {
+      background: var(--md-code-bg);
+      cursor: default;
+      opacity: 0.88;
+    }
+    .me-wrapper.me-readonly .me-toolbar {
+      opacity: 0.45; pointer-events: none;
+    }
+
+    /* ============ 高亮标记 ============ */
+    .me-preview mark {
+      background: rgba(250, 204, 21, 0.3);
+      color: inherit;
+      padding: 0.1em 0.2em;
+      border-radius: 3px;
+    }
+
+    /* ============ 打印样式 ============ */
+    @media print {
+      .me-wrapper { border: 0 !important; box-shadow: none !important; }
+      .me-toolbar, .me-statusbar, .me-divider { display: none !important; }
+      .me-body.me-mode-split .me-editor-pane { display: none; }
+      .me-body.me-mode-split .me-preview-pane { flex: 1 1 100% !important; }
+      .me-preview { padding: 0 !important; font-size: 11pt; }
+      .me-wrapper.me-fullscreen { position: static !important; width: auto !important; height: auto !important; }
+    }
   `;
 };