Refactor and enhance type hints across multiple modules

- Updated the `from_tuple` method in `Prof` class to specify return type.
- Added type hints for various methods in `LehmannsClient`, `OpenAI`, `WebRequest`, and `ZoteroController` classes to improve code clarity and type safety.
- Modified `pdf_to_csv` function to return a string instead of a DataFrame.
- Enhanced error handling and type hints in `wordparser` and `xmlparser` modules.
- Removed unused UI file `Ui_medianadder.ts`.
- Improved the layout and structure of the `semesterapparat_ui` to enhance user experience.
- Updated file picker to support `.doc` files in addition to `.docx`.
- Added unique item handling in `Ui` class to prevent duplicates in apparat list.
- General code cleanup and consistency improvements across various files.

src/logic/SRU.py

@@ -86,7 +86,7 @@ def _text(elem: Optional[ET.Element]) -> str:
     return (elem.text or "") if elem is not None else ""
 
 
-def _req_text(parent: ET.Element, path: str) -> str:
+def _req_text(parent: ET.Element, path: str) -> Optional[str]:
     el = parent.find(path, NS)
     if el is None or el.text is None:
         return None
@@ -98,7 +98,7 @@ def parse_marc_record(record_el: ET.Element) -> MarcRecord:
     record_el is the <marc:record> element (default ns MARC in your sample)
     """
     # leader
-    leader_text = _req_text(record_el, "marc:leader")
+    leader_text = _req_text(record_el, "marc:leader") or ""
 
     # controlfields
     controlfields: List[ControlField] = []
@@ -124,8 +124,8 @@ def parse_marc_record(record_el: ET.Element) -> MarcRecord:
 
 
 def parse_record(zs_record_el: ET.Element) -> Record:
-    recordSchema = _req_text(zs_record_el, "zs:recordSchema")
-    recordPacking = _req_text(zs_record_el, "zs:recordPacking")
+    recordSchema = _req_text(zs_record_el, "zs:recordSchema") or ""
+    recordPacking = _req_text(zs_record_el, "zs:recordPacking") or ""
 
     # recordData contains a MARC <record> with default MARC namespace in your sample
     recordData_el = zs_record_el.find("zs:recordData", NS)
@@ -140,7 +140,7 @@ def parse_record(zs_record_el: ET.Element) -> Record:
 
     marc_record = parse_marc_record(marc_record_el)
 
-    recordPosition = int(_req_text(zs_record_el, "zs:recordPosition"))
+    recordPosition = int(_req_text(zs_record_el, "zs:recordPosition") or "0")
     return Record(
         recordSchema=recordSchema,
         recordPacking=recordPacking,