docs: move BEDIENUNGSANLEITUNG and INSTALL_FROM_ARCHIVE into docs/

Keep only README, LICENSE, and CHANGELOG as prose at the repo root
(tooling/convention) and move the remaining manuals under docs/ next to
SECURITY_AND_OPERATIONS.md.

- git mv the two files into docs/ (history preserved).
- Update all cross-references: README doc-index links, the internal
  SECURITY_AND_OPERATIONS link and the §12 pointer list in
  BEDIENUNGSANLEITUNG, and the repo inventory in SECURITY_AND_OPERATIONS §1.
- build_archive.py: point REQUIRED_FILES at docs/ and drop the now-redundant
  INCLUDE_FILES entries (the docs/ dir is included wholesale).
- build_archive.py: drop the obsolete requirements.txt<->pyproject dependency
  mirror check, which broke once requirements.txt was reduced to `.`
  (pyproject is the single source of truth). Verified by building and
  re-opening the archive.

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

docs/SECURITY_AND_OPERATIONS.md

@@ -43,9 +43,10 @@ scripts/smoke.sh          Opt-in End-to-End-Rauchtest gegen echten Docker + GPU
                           `git config core.hooksPath .githooks`
 .forgejo/workflows/ci.yml Forgejo-Actions-CI (läuft, sobald ein Runner registriert ist)
 README.md                 Schnelleinstieg + Doku-Index
-BEDIENUNGSANLEITUNG.md    Vollständiges Benutzerhandbuch
-INSTALL_FROM_ARCHIVE.md   Installation aus dem Archiv + Archiv bauen/verifizieren
 CHANGELOG.md / LICENSE    Versionshistorie / MIT-Lizenz
+docs/BEDIENUNGSANLEITUNG.md    Vollständiges Benutzerhandbuch
+docs/INSTALL_FROM_ARCHIVE.md   Installation aus dem Archiv + Archiv bauen/verifizieren
+docs/SECURITY_AND_OPERATIONS.md  Dieses Dokument (Architektur/Sicherheit/Betrieb)
 ```
 
 ## 2. Konfigurationsmodell