feat(filters): upgrade markdown-normalizer to v1.2.7

- Fix Issue #49: resolve greedy regex matching in consecutive emphasis
- Add LaTeX formula protection to prevent corruption of \times, \nu, etc.
- Expand i18n support to 12 languages with strict alignment
- Fix NameError in Request import during testing

plugins/debug/verify_fix_v126.py

@@ -0,0 +1,42 @@
+import re
+
+def verify_fix_v126():
+    # 1. 准备触发 Bug 的测试文本
+    test_cases = [
+        "I **prefer** tea **to** coffee.",                  # 标准 Issue #49 案例
+        "The **quick** brown **fox** jumps **over**.",       # 多个加粗块
+        "** text ** and ** more **",                       # 需要修复的内部空格
+        "Calculations: 2 * 3 * 4 = 24",                     # 不应被识别为强调的数学公式
+    ]
+
+    # 2. 使用 v1.2.6 中的核心正则表达式 (移除了可能引起解析错误的中文注释)
+    # 模式: (?<!\*|_)(\*{1,3}|_{1,3})(?P<inner>(?:(?!\1)[^\n])*?)(\1)(?!\*|_)
+    pattern_str = r"(?<!\*|_)(\*{1,3}|_{1,3})(?P<inner>(?:(?!\1)[^\n])*?)(\1)(?!\*|_)"
+    FIX_REGEX = re.compile(pattern_str)
+
+    def fixed_normalizer(content):
+        def replacer(match):
+            symbol = match.group(1)
+            inner = match.group("inner")
+            
+            stripped_inner = inner.strip()
+            
+            # 只有当确实有空格需要修，且内部不是空的才修复
+            if stripped_inner != inner and stripped_inner:
+                return f"{symbol}{stripped_inner}{symbol}"
+            return match.group(0)
+
+        # 模拟插件循环处理
+        for _ in range(2):
+            content = FIX_REGEX.sub(replacer, content)
+        return content
+
+    print("--- v1.2.6 Fix Verification ---")
+    for text in test_cases:
+        result = fixed_normalizer(text)
+        print(f"Input:  {text}")
+        print(f"Output: {result}")
+        print("-" * 30)
+
+if __name__ == "__main__":
+    verify_fix_v126()