[feat][formatter] Integrate LaTeX formatter for improved formula readability

- Add latex_formatter.py based on tex-fmt (https://github.com/WGUNDERWOOD/tex-fmt)
- Update to_katex.py to use the new formatter
- Enhance LaTeX formula output with better formatting and readability

This integration helps make generated LaTeX formulas more readable and
maintainable by applying consistent formatting rules.

texteller/models/ocr_model/utils/to_katex.py

@@ -1,5 +1,7 @@
 import re
 
+from .latex_formatter import format_latex
+
 
 def change(input_str, old_inst, new_inst, old_surr_l, old_surr_r, new_surr_l, new_surr_r):
     result = ""
@@ -185,4 +187,8 @@ def to_katex(formula: str) -> str:
     # remove extra spaces (keeping only one)
     res = re.sub(r' +', ' ', res)
 
-    return res.strip()
+    # format latex
+    res = res.strip()
+    res, logs = format_latex(res)
+
+    return res