release: v0.1.4 — parser enhancement, new syntax, performance optimization

feat(parser): comprehensive Markdown parser enhancement
- Add nested list support (multi-level unordered/ordered, mixed nesting)
- Add Setext headings (=== / ---)
- Add indented code blocks (4-space indent)
- Add HTML comment passthrough (<!-- -->)
- Add entity reference protection (&amp; &#169;)
- Add ordered list start attribute
- Add link title single-quote support
- Add LaTeX math formulas ($inline$ / $$block$$)
- Add footnote support ([^1] ref + [^1]: definition)
- Add definition lists (term\n: definition)
- Extend emoji map from 85 to 150+ common emojis
- Fix backtick code block matching (CommonMark spec)
- Fix italic regex character truncation (lookbehind assertions)
- Fix superscript/subscript/strikethrough ambiguity
- Fix blockquote prefix handling (>text without space)
- Enhance safeUrl filtering (additional protocol checks)
- Enhance slugify (Unicode NFKC normalization)

perf(parser): single-pass inline scanning, render cache, pre-compiled regex
- Replace 14-step chained regex with unified single-pass scanInline()
- Add cachedRenderInline() with FIFO LRU eviction (300-entry cap)
- Pre-compile 15+ static regex constants for block boundary detection
- Skip redundant style='text-align:left' on default-aligned table cells

style(parser): add CSS for footnotes, definition lists, math formulas, sup/sub

test(parser): 44 new test cases covering all v0.1.4 syntax additions (469 total)

chore: bump version 0.1.3 → 0.1.4 across all source files, docs, site pages

site/index.html

@@ -467,8 +467,8 @@
         <div class="feature-icon">
           <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><polyline points="16 18 22 12 16 6"/><polyline points="8 6 2 12 8 18"/></svg>
         </div>
-        <h3>内置轻量解析器</h3>
-        <p>自研 CommonMark 子集 + GFM 扩展解析器，覆盖标题、表格、任务列表、代码块等常用语法，也可整体替换。</p>
+        <h3>内置增强解析器</h3>
+        <p>自研 CommonMark + GFM 扩展解析器，覆盖数学公式、脚注、嵌套列表、定义列表、表格对齐、任务列表等丰富语法，也可整体替换。</p>
       </div>
       <div class="feature">
         <div class="feature-icon">