docs: anchor documentation rules, rebuild index, archive proposal

- REPO_MAP.md: replace Arbeitsregel with 8 binding documentation rules
  (one fact one home, done leaves the working copy, file types, header
  convention, quarterly gardening)
- WORKFLOW.md Dokumentationspflicht and CLAUDE.md aligned to the rules
- docs/README.md index rebuilt for the consolidated state
- H drive docs merged into ops/h-drive-nearline/README.md (scheduled
  task + no-MIR rule added); docs/H_DRIVE_NEARLINE_PULL.md removed
- implemented proposal archived to docs/archive/2026/

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/archive/README.md

@@ -22,3 +22,4 @@ archiviert, sondern geloescht (Git-Historie ist das Archiv).
 | `2026/boot-cleanup-plan-2026-06-04.md` | BCD-/Boot-Bereinigungsplan | Umgesetzt; Endzustand im System-Audit belegt |
 | `2026/postinstall-erstes-ziel-codex.md` | Postinstall-Arbeitsauftrag | Projekt abgeschlossen |
 | `2026/baerchen-app-license-readiness-2026-06-06.md` | App-/Lizenz-Readiness-Check | Projekt abgeschlossen |
+| `2026/homelab-doku-optimierung-2026-06-11.md` | Analyse + Vorschlag zur Doku-Konsolidierung | umgesetzt 2026-06-11; Regeln in `docs/REPO_MAP.md`, Entscheidung in `docs/DECISIONS.md` |