Final documentation and submission cleanup

[FriggemannMichael]

Objective:
Prepare the repository for final submission.

Acceptance criteria:

• README accurately describes setup, checks, and known project behavior.
• requirements.txt is complete and reproducible.
• Database and local files are not tracked.
• No commented-out code, print debugging, or unrelated files remain.
• Ruff, Django checks, and tests pass from the local virtual environment.
• docs/checkliste.md and docs/endpoints.md are reviewed against the implementation.

[FriggemannMichael]

TDD workflow for this project:

• Define the expected behavior before implementing the endpoint or model behavior.
• Write or outline the failing test first.
• Implement only enough code to make that test pass.
• Refactor after the test passes.
• Keep Django check, Ruff, and the relevant tests green from the local virtual environment.

[FriggemannMichael]

Follow-up bugs found during the docs-vs-implementation review (see acceptance criterion "docs/checkliste.md and docs/endpoints.md are reviewed against the implementation"). Tracked separately so this issue stays a clean submission checklist:

• PATCH /api/orders/{id}/ returns 404 instead of 403 for a non-owner business user #29 — PATCH /api/orders/{id}/ returns 404 instead of the documented 403 for a non-owner business user
• Orders permissions/get_queryset raise 500 for users without a UserProfile #30 — Orders permissions/get_queryset raise 500 for users without a UserProfile

[FriggemannMichael]

Submission cleanup complete — closing summary. All acceptance criteria met:

• README rewritten with a project overview, feature list, user-type/auth notes, and accurate project structure (Rewrite README with project overview and features #35).
• requirements.txt pinned and reproducible — pip freeze matches the file (Pin missing type-stub dependencies in requirements.txt #36).
• Database and local files are not tracked; .gitignore covers db.sqlite3, .venv/, media/, staticfiles/, IDE and env files (verified clean).
• No print() debugging, commented-out code, or unrelated files remain (verified clean).
• Ruff (incl. D101), Django checks, and pytest all pass locally; coverage ~99%.
• docs/endpoints.md is cross-checked against the implementation by the contract test (no remaining xfail markers).