release: v0.1.7 — editing experience: gutter, auto-format, bracket close, drag-drop, outline

feat(core): line number gutter with current line highlight
- .me-gutter rendered alongside textarea, sync-scrolls with content
- .me-gutter-active highlights the line containing the cursor
- config.lineNumbers (default true) to toggle

feat(core): smart Enter auto-formatting
- List continuation: '- ' / '1. ' auto-insert on Enter at end of list item
- Ordered list auto-increment: '1.' → '2.'
- Quote continuation: '> ' auto-insert on Enter at end of quote line
- Empty list/quote item: Enter removes the marker (end list)

feat(core): bracket/quote auto-close
- (), [], {}, <>, "", '', ``, **, __ auto-close pairs
- Selection wrapping: select text then press ( → wraps as (text)
- config.autoBrackets (default true) to toggle

feat(core): drag & drop file support
- Drop image files → auto base64 inline insert ![](data:...)
- Drop text/code files → insert file contents
- Drop external text from browser → insert at cursor

feat(core): outline/TOC panel
- Extracts headings from rendered HTML preview
- Nested tree with indentation by heading level
- Click to scroll-jump in both preview and textarea
- config.outline (default false) to toggle

style: gutter, outline panel, current line highlight CSS

test: 11 new tests for gutter, auto-format, bracket close, outline (532 total)

chore: bump version 0.1.6 → 0.1.7 across all files, site, types

site/docs.html

@@ -175,7 +175,7 @@
 
 <header class="docs-header">
   <h1><span class="grad">文档</span></h1>
-  <p class="sub">MetonaEditor v0.1.6 完整 API、配置与使用指南</p>
+  <p class="sub">MetonaEditor v0.1.7 完整 API、配置与使用指南</p>
 </header>
 
 <div class="container">
@@ -618,7 +618,7 @@ i18nUtils<span class="c-punc">.</span><span class="c-fn">formatDate</span><span
 
 <footer>
   <div class="container">
-    MetonaEditor v0.1.6 · <a href="https://git.metona.cn/MetonaTeam/MetonaEditor" target="_blank" rel="noopener">源码仓库</a> · MIT License
+    MetonaEditor v0.1.7 · <a href="https://git.metona.cn/MetonaTeam/MetonaEditor" target="_blank" rel="noopener">源码仓库</a> · MIT License
   </div>
 </footer>