docs: Gate 5 closeout - AAR, harvest, design doc done

The design doc closes with its AAR (planned/actual/why/learnings, the
six acceptance criteria checked off 6/6, the session's shakiest calls
named) and moves to docs/design/done/ with status done. Harvest: a
stolpersteine wiki page distilled from the AAR (hex is not a git SHA,
TZ on the git process, python floor, anonymous Gitea negatives,
negative tests, directory links), and the neckbeard feedback list
becomes issue 0040 - a deliberate separate act, per the design's
non-goals. Operational follow-up is issues 0041 (refine imported
wartegrund) and 0042 (go-live: push, first mirror run, CI schedule,
milestone for gitops#61). Final chain green: validate 0/0 over 36 open
issues, gen_status --check current, drift 0, prosa 0.

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

docs/sources/upstream/neckbeard-v0.1.1/HERKUNFT.md

@@ -5,7 +5,7 @@ Unveränderte Originale aus **neckbeard v0.1.1**, Commit
 `https://git.lab/oss-projekte/ai/neckbeard.git` — der Stand, gegen den
 der Feldtest (Branch `Neckbeard-v0.1.1-analyse-1`) gemessen hat und aus
 dem die Migration übernommen wurde (Design:
-`docs/design/2026-08-11-neckbeard-migration.md`).
+`docs/design/done/2026-08-11-neckbeard-migration.md`).
 
 Zweck: Byte-Baseline für `scripts/pruefe_upstream_drift.py`. Ein
 Framework-Upgrade ersetzt diese Dateien bewusst und in einem eigenen