docs: remove redundant docs, fold migration table into README

Clean up documentation redundancy:

- Delete docs/Archiv_fertig_-_Check_und_Installation.md: an AI hand-off
  transcript (first-person, stale test count, malformed markdown) whose
  useful content is already in INSTALL_FROM_ARCHIVE.md.
- Delete docs/How_to_use.md after moving its one unique asset -- the
  old-script -> new-command migration table -- into the README; drop it
  from the build_archive manifest.
- Fix INSTALL_FROM_ARCHIVE.md drift: list LICENSE/CHANGELOG.md in the
  archive allowlist and use `python -m pytest`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

build_archive.py

@@ -72,7 +72,6 @@ REQUIRED_FILES = [
     "tests/test_http_ops.py",
     "tests/test_lock_ops.py",
     "tests/test_actions.py",
-    "docs/How_to_use.md",
     "scripts/smoke.sh",
     "BEDIENUNGSANLEITUNG.md",
     "INSTALL_FROM_ARCHIVE.md",