init: WordFileParse docx→HTML 解析服务（含 Word EQ 域公式修复）

服务：Spring Boot 3.2 + docx4j 8.3.9，POST /api/v3/server_office_file/file/parse
      接受 .docx，返回 HTML（公式 → LaTeX，图片 → RustFS 外链）

公式支持三类来源：
- OMML（Word 2007+ 公式）      → Python omml_mathml2latex
- MathType OLE 对象            → Ruby mathtype2mathml → MathML → LaTeX
- Word EQ 域（老教辅主力）      → EqToLatexUtil（本次新增）

本次改动：
1. 新增 java-svc/.../core/EqToLatexUtil.java：
   移植自 jby backend-services office-core，EQ 语法 → LaTeX
   （\f→\dfrac、\r→\sqrt、\i→\int/\sum/\prod、\s→^{}/_{}、\b→\left\right、
     \a→array、\x→\boxed/\overline、\o\al 堆叠、圈码、化学符号、极限、连等式）
   品牌标记 JBYU* → WPU*，与采集端一致
2. CtoMathFinder：接上 EQ 分支（原为 not-ported 桩），域代码经
   EqToLatexUtil.convert 转 LaTeX 写入 eqLatexMap（WPEQNUM 占位符）
3. WordParseUtil.dealPlaceholder：EQ 的 LaTeX 同样加 \( \) 包裹
   （原先因 WPEQNUM 例外不加包裹，前端/MathJax 不渲染）

修前症状：教辅 Word 里分式/方程组/上下标整段丢失（如 {−1/3, 1} 变成 {－，1}）
修后实测：46 份教辅 2908 处 EQ 域全部还原，公式总数 2954 处、零未包裹残留

安全：application.yml（含 RustFS 密钥）不入库，提供 application.yml.example；
      OssService 的 @Value 默认密钥已清空

scripts/omml_mathml2latex/parsers/mathml_parser.py

@@ -0,0 +1,168 @@
+"""
+MathML parser for direct MathML input.
+
+This parser handles MathML XML input, performing validation and extraction
+of individual math equations.
+"""
+
+import sys
+from typing import List
+from pathlib import Path
+from lxml import etree as ET
+from ..core.interfaces import Parser
+
+# Import utilities from omml_to_tex package for HTML entity decoding and equation extraction
+sys.path.insert(0, str(Path(__file__).parent.parent.parent))
+from ..utils import decode_html_entities, extract_math_equations
+
+
+class MathMLParser(Parser):
+    """
+    Parser for MathML XML input.
+
+    This parser handles direct MathML XML input, performing basic validation
+    and extracting individual <math> elements.
+
+    Examples:
+        Single equation:
+            >>> parser = MathMLParser()
+            >>> mathml = "<math><mi>x</mi></math>"
+            >>> results = parser.parse(mathml)
+            >>> len(results)
+            1
+
+        Multiple equations:
+            >>> parser = MathMLParser()
+            >>> mathml = "<root><math><mi>x</mi></math><math><mi>y</mi></math></root>"
+            >>> results = parser.parse(mathml)
+            >>> len(results)
+            2
+    """
+
+    def __init__(self):
+        """Initialize the MathML parser."""
+        pass
+
+    def parse(self, source: str) -> List[str]:
+        """
+        Parse MathML input and return list of MathML equation strings.
+
+        Args:
+            source: MathML XML string or file path
+
+        Returns:
+            List of MathML equation strings (one per <math> element)
+
+        Raises:
+            ValueError: If input is not valid MathML XML
+            RuntimeError: If parsing fails
+
+        Examples:
+            >>> parser = MathMLParser()
+            >>> mathml = "<math><mi>x</mi><mo>+</mo><mi>y</mi></math>"
+            >>> results = parser.parse(mathml)
+            >>> len(results)
+            1
+            >>> '<mi>x</mi>' in results[0]
+            True
+        """
+        import os
+
+        # Check if source is a file path
+        if os.path.exists(source):
+            try:
+                with open(source, 'r', encoding='utf-8') as f:
+                    source = f.read()
+            except (IOError, UnicodeDecodeError) as e:
+                raise ValueError(f"Failed to read MathML file: {e}")
+
+        # STRATEGY 1: Try regex-based extraction first (handles multi-equation files + HTML entities)
+        # This is the same approach as the original omml_to_tex.py
+        try:
+            equations = extract_math_equations(source)
+            if equations:
+                return equations
+        except Exception:
+            # If regex extraction fails, fall through to XML parsing
+            pass
+
+        # STRATEGY 2: Try XML parsing as fallback (single well-formed document)
+        try:
+            root = ET.fromstring(source.encode('utf-8'))
+        except ET.XMLSyntaxError as e:
+            raise ValueError(f"Invalid XML syntax: {e}")
+
+        # Find all <math> elements
+        math_elements = []
+
+        # Check if root itself is a <math> element
+        if self._is_math_element(root):
+            math_elements.append(root)
+        else:
+            # Search for <math> elements (with or without namespace)
+            math_elements.extend(root.findall('.//{http://www.w3.org/1998/Math/MathML}math'))
+            math_elements.extend(root.findall('.//math'))
+
+        if not math_elements:
+            # No <math> elements found - treat entire document as one equation if it looks like MathML
+            if self._looks_like_mathml(root):
+                math_elements.append(root)
+            else:
+                raise ValueError("No <math> elements found in MathML input")
+
+        # Convert each <math> element to string
+        results = []
+        for math_elem in math_elements:
+            mathml_str = ET.tostring(math_elem, encoding='unicode')
+            results.append(mathml_str)
+
+        return results
+
+    def can_handle(self, source: str) -> bool:
+        """
+        Check if this parser can handle the given input source.
+
+        Args:
+            source: Input source to check
+
+        Returns:
+            True if source appears to be MathML, False otherwise
+
+        Examples:
+            >>> parser = MathMLParser()
+            >>> parser.can_handle("<math><mi>x</mi></math>")
+            True
+            >>> parser.can_handle("<m:oMath>...</m:oMath>")
+            False
+        """
+        # Check for MathML markers
+        content_start = source.strip()[:200]
+        return '<math' in content_start or '<mml:math' in content_start
+
+    @property
+    def parser_type(self) -> str:
+        """Get the parser type identifier."""
+        return "mathml"
+
+    def _is_math_element(self, element: ET.Element) -> bool:
+        """Check if element is a <math> element."""
+        local_name = element.tag.split('}')[-1] if '}' in element.tag else element.tag
+        return local_name == 'math'
+
+    def _looks_like_mathml(self, element: ET.Element) -> bool:
+        """Check if element tree looks like MathML content."""
+        # Check for common MathML element tags
+        mathml_tags = {'mi', 'mo', 'mn', 'mrow', 'mfrac', 'msup', 'msub', 'mtext'}
+
+        # Get all element tags in tree
+        all_tags = set()
+        for elem in element.iter():
+            local_name = elem.tag.split('}')[-1] if '}' in elem.tag else elem.tag
+            all_tags.add(local_name)
+
+        # If at least 2 MathML tags present, consider it MathML
+        return len(all_tags & mathml_tags) >= 2
+
+    def __repr__(self) -> str:
+        """String representation for debugging."""
+        return "MathMLParser()"