Add ODF (.ods) support via odfpy

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

excel_import/reader.py

@@ -5,8 +5,17 @@ import pandas as pd
 from .config import SheetConfig
 
 
+_ENGINES = {
+    ".xls": "xlrd",
+    ".xlsx": "openpyxl",
+    ".xlsm": "openpyxl",
+    ".xlsb": "openpyxl",
+    ".ods": "odf",
+}
+
+
 def _engine_for(path: Path) -> str:
-    return "xlrd" if path.suffix.lower() == ".xls" else "openpyxl"
+    return _ENGINES[path.suffix.lower()]
 
 
 class ExcelReader:
@@ -14,7 +23,7 @@ class ExcelReader:
         self.path = Path(path)
         if not self.path.exists():
             raise FileNotFoundError(f"Excel file not found: {self.path}")
-        if self.path.suffix.lower() not in {".xls", ".xlsx", ".xlsm", ".xlsb"}:
+        if self.path.suffix.lower() not in _ENGINES:
             raise ValueError(f"Unsupported file type: {self.path.suffix}")
 
     def sheet_names(self) -> list[str]: