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/utils/helpers.py

@@ -0,0 +1,136 @@
+"""
+Pattern and symbol replacement helper functions.
+
+This module provides utilities for applying symbol mappings and regex patterns
+to text, used throughout the conversion pipeline.
+"""
+
+import re
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+def apply_symbol_replacements(text: str, mapping: dict) -> str:
+    """Apply simple symbol replacements from a mapping dictionary.
+
+    Args:
+        text: Input text
+        mapping: Dictionary of {symbol: replacement}
+
+    Returns:
+        Text with all symbols replaced
+
+    Example:
+        >>> mapping = {'α': '\\\\alpha', 'β': '\\\\beta'}
+        >>> apply_symbol_replacements('α + β', mapping)
+        '\\\\alpha + \\\\beta'
+    """
+    for symbol, replacement in mapping.items():
+        text = text.replace(symbol, replacement)
+    return text
+
+
+def apply_pattern_replacements(text: str, patterns: list, verbose: bool = False) -> str:
+    """Apply regex pattern replacements from a list of (pattern, replacement, description) tuples.
+
+    Args:
+        text: Input text
+        patterns: List of (pattern, replacement, description) tuples
+        verbose: If True, log each replacement
+
+    Returns:
+        Text with all patterns applied
+
+    Example:
+        >>> patterns = [(r' {3,}', '  ', 'Reduce multiple spaces')]
+        >>> apply_pattern_replacements('a    b', patterns)
+        'a  b'
+    """
+    for pattern, replacement, description in patterns:
+        if verbose:
+            count = len(re.findall(pattern, text))
+            if count > 0:
+                logger.debug(f"Applying: {description} ({count} matches)")
+        text = re.sub(pattern, replacement, text)
+    return text
+
+
+def apply_unicode_symbol_mapping(
+    text: str,
+    unicode_to_latex: dict,
+    additional_replacements: dict = None,
+    subscript_context: bool = False
+) -> str:
+    """Apply Unicode to LaTeX symbol mapping.
+
+    Args:
+        text: Input text containing Unicode symbols
+        unicode_to_latex: Main Unicode to LaTeX mapping dictionary
+        additional_replacements: Optional additional symbol replacements
+        subscript_context: If True, use subscript-specific mappings (with spaces)
+
+    Returns:
+        Text with Unicode symbols converted to LaTeX
+
+    Example:
+        >>> mapping = {'α': '\\\\alpha', '→': '\\\\to'}
+        >>> apply_unicode_symbol_mapping('α → β', mapping, {})
+        '\\\\alpha \\\\to β'
+    """
+    # First apply standard UNICODE_TO_LATEX mapping
+    for symbol, latex in unicode_to_latex.items():
+        text = text.replace(symbol, latex)
+
+    # In subscript context, apply additional replacements with proper spacing
+    if subscript_context and additional_replacements:
+        for symbol, latex in additional_replacements.items():
+            text = text.replace(symbol, latex)
+
+    return text
+
+
+def is_default_color(color: str) -> bool:
+    """Check if a color value represents the default (black) color.
+
+    Args:
+        color: Color value in various formats (hex, name, rgb)
+
+    Returns:
+        True if the color is black/default, False otherwise
+
+    Examples:
+        >>> is_default_color('#000000')
+        True
+        >>> is_default_color('#000')
+        True
+        >>> is_default_color('black')
+        True
+        >>> is_default_color('rgb(0, 0, 0)')
+        True
+        >>> is_default_color('#FF0000')
+        False
+        >>> is_default_color('red')
+        False
+    """
+    if not color:
+        return False
+
+    # Normalize the color string
+    color_lower = color.lower().strip()
+
+    # Check for common black color representations
+    black_colors = {
+        '#000000',  # Full hex
+        '#000',     # Short hex
+        'black',    # Named color
+        'rgb(0,0,0)',  # RGB without spaces
+        'rgb(0, 0, 0)',  # RGB with spaces
+        'rgba(0,0,0,1)',  # RGBA without spaces
+        'rgba(0, 0, 0, 1)',  # RGBA with spaces
+    }
+
+    # Remove all whitespace for comparison
+    color_normalized = ''.join(color_lower.split())
+
+    return color_normalized in {c.replace(' ', '') for c in black_colors}