[proposal] integration tests

[pellepelster]

hi,

I wanted to tackle some minor issues I had and to make sure I dot not break anything critical I thought it might be a good idea to start with a full E2E integration tests. Some notes on the implementation

• for tooling setup I used mise, to keep local development and CI as close together as possible and make setup and debugging a little bit easier and more developer friendly
• I deliberately wanted to do the tests not in Rust and have a fully cycle with backup and restore using the compiled binary
  • using python for tool calling felt like a natural choice here for me
  • restore data is extracted from the real produced PDFs to make sure the that the data really can be restored
    • the text retrieval is a little brittle and might be sensitive to layout changes, but given the nature of the tool I think this is acceptable to make sure the restore works
• I kept the workflow separate for now, but i could of course be integrated with the existing workflows