SEC-020: MAAS admin-account recovery -- consolidate `admin`, mint `operator`, creds-audit CLEAN x3 ...

Operator task: recover the MAAS admin accounts and save the creds retrievably.
The task premise was FALSIFIED by measurement before any mutation: the ledger's
2026-07-25 "MAAS web-GUI login does NOT exist / never minted" was wrong. The
`admin` password was minted 2026-07-13 by site-headend-install.sh:452 and is
MEASURED working (login 204 vs 400 wrong-password control). It was merely
root-only on voffice1 and un-consolidated -- the SEC-009 miss class, not a
missing account. Scope re-ruled by the operator after that finding:
"New account + consolidate only" -- no existing password rotated.

- NEW MAAS superuser `operator` for human GUI login; password generated on
  vcloud, set via stdin (never argv -- SEC-018 discipline; changepassword has
  no --password and createadmin --password would expose it).
- `admin` password CONSOLIDATED byte-identical (sha256-verified) to
  ~/vr1-office1-creds/. NOT rotated, so the VM copy REMAINS source-of-record;
  a future rotation must update both or the VM copy becomes a stale trap.
- juju-vr1-dc0/dc1 untouched BY RULING: their SEC-018/019 API keys are
  load-bearing for the blocked Stage-5 bootstrap.
- Manifest backfill -> creds-audit CLEAN on all three sites (was RED: dc0 3 +
  dc1 1 undeclared), closing the dc0 edge-keypair queued finding named in
  vr1-dc1.manifest:18-20.
- Root cause recorded: `admin` doubles as the automation identity (19 `maas
  admin` call sites in 4 scripts), so automation never needed the password and
  nothing forced it into the folder. Proposable as the next-free D-number
  [ARCH]; NOT assigned (GA-R3 doubt-resolves-DOWN).
- Falsified ledger claim struck+corrected; machine-derived block re-seeded
  (was stale on every line: SEC 12->16, next-free D 133->137, DOCFIX 200->204).

Evidence: docs/audit/maas-admin-recovery-20260725.txt (generated, no secret
values; scanned for password bytes = 0 hits with a planted-control check).
repo-lint 0 fail; gauntlet ALL GREEN (79).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HvCyrwvYTTcDYnRErfMsNf