docs(runbooks): the PR flow, not git push origin main -- that instruction is now blocked

main became a protected branch on 2026-09-29, so the direct push that 37 of 39 runbooks
instructed is REJECTED. The wording was merely stale before; it is now actively wrong,
and it is the line an operator reads mid-incident.

Every occurrence now describes the real path: push a branch, open a PR, merge once the
gate is green -- that merge is the deploy. 35 files shared one identical block;
flux-reconcile.md, README.md and plex-claim.md each said it their own way and were
corrected individually.

plex-claim.md is rewritten around the delivery loop and records that THE SERVER IS NOW
CLAIMED (PlexOnlineToken present in /config), so PLEX_CLAIM is a permanent no-op and the
page only applies after a /config wipe.

Adds infra/plex/claim-ship.sh, which drives branch -> commit -> push -> PR -> gate ->
merge -> reconcile -> pod roll -> verdict with a stopwatch. Three steps are easy to lose
under time pressure and two are SILENT when skipped: --with-source (without it the
Kustomization applies the previously-fetched revision), the mandatory rollout restart
(only the ciphertext changes, so the pod template is byte-identical and nothing restarts
itself), and the feat/ branch prefix (act_runner capacity is 1, and a prefix inside
gate.yml's push trigger fires a redundant run that serialises ahead of the PR run).

Drops the "~4-minute TTL" the page asserted in four places. It was uncited, and upstream
pms-docker documents no expiry at all. The countdown on plex.tv/claim is the authority.
Measured loop: ~2m45s.

DECISIONS-LOG carries the PM handoff: both halves of the 2026-08-31 CI claim were false,
the stale-.runner root cause, the four-deep Flux dependency cascade, and the correction
that a skipped Gitea job reports success rather than hanging.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

runbooks/node-disk.md

@@ -56,8 +56,10 @@ a cluster holding 6 Velero backups and 27 CNPG backups. Verified on prod 2026-09
 `settings.longhorn.io`, `volumes.longhorn.io`, `nodes.longhorn.io`.
 
 Mutating kubectl (`apply`, `patch`, `annotate`, `rollout`) and `flux reconcile` are blocked for
-agents here: every durable change goes through git (`git push origin main` **is** the deploy).
-Where this runbook gives a mutating command it is for an operator, and it says so.
+agents here: every durable change goes through git. **`main` is a protected branch — a direct push
+is rejected.** A change lands by pushing a branch, opening a PR, and merging it once the gate is
+green; that merge is the deploy. Where this runbook gives a mutating command it is for an operator,
+and it says so.
 
 ## First commands