[BUG]: 'Union' not defined in main.py

[Cubix33]

⚡️ Describe the Bug

Running the application via the make exec command crashes immediately upon startup with a NameError: name 'Union' is not defined. This occurs because Union is used for type hinting the pdf_form_path parameter in the run_pdf_fill_process function signature in src/main.py, but the module is never imported.

👣 Steps to Reproduce

1. Ensure the Docker containers are running (docker compose up -d).
2. Run the command make exec (or docker compose exec app python3 src/main.py) in the terminal.
3. See the NameError crash output immediately.

📉 Expected Behavior

The application should start successfully, detect the PDF, and begin the extraction/filling process without throwing Python standard library import errors.

🖥️ Environment Information

• OS: Windows / WSL 2 (Ubuntu)
• Docker/Compose Version: Docker Desktop latest
• Ollama Model used: Mistral

📸 Screenshots/Logs

Traceback (most recent call last):
  File "/app/src/main.py", line 14, in <module>
    def run_pdf_fill_process(user_input: str, definitions: list, pdf_form_path: Union[str, os.PathLike]):
                                                                                ^^^^^
NameError: name 'Union' is not defined

🕵️ Possible Fix

Add the missing import statement from the standard typing library at the top of src/main.py:

from typing import Union