infra(gitea): recover the Actions runner before anything requires the gate

No runner is registered at repo, org or site level, so gate.yml has never executed.
PR #1 sat pending for 30.6 minutes across 122 polls and never reported. Requiring the
gate as a status check in that state would lock the repo permanently.

Adds runner-token-rotate.sh: mints a fresh instance-level registration token from the
Gitea API and writes it into the SOPS secret via sops set, without ever printing the
value.

Records the likely root cause, which a new token alone does NOT fix. act_runner
registers once and persists its identity in /data/.runner on the act-runner-data PVC.
If Gitea no longer holds a matching runner row, the pod starts, sees .runner, SKIPS
registration entirely, and polls with an identity Gitea does not recognise. Symptom:
zero runners, pod running, nothing obviously broken. Clearing the PVC is what forces a
genuine re-registration.

The README now sequences runner-first, enforcement-second, and requires CONFIRMING the
runner reports online rather than assuming it. That assumption is the whole defect:
DECISIONS-LOG recorded the runner as online on 2026-08-31 and nobody checked since.

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

infra/gitea/README.md

@@ -27,12 +27,28 @@ do not trust the API response**, since Gitea may let site admins bypass protecti
 It authenticates with the credential `git` already has stored for this host, and never
 prints the secret.
 
+## `runner-token-rotate.sh`
+
+Mints a fresh instance-level registration token from the Gitea API and writes it into
+`apps/wave-1/gitea-actions-runner-secret.sops.yaml` via `sops set`. **The token value is
+never printed.**
+
+    ./infra/gitea/runner-token-rotate.sh
+
+A fresh token is usually **not sufficient on its own**. `act_runner` registers exactly once
+and persists its identity in `/data/.runner` on the `act-runner-data` PVC. If Gitea no
+longer holds a matching runner row, the pod starts, sees `.runner`, **skips registration**,
+and polls with an identity Gitea does not recognise — so it never appears in the runner
+list. That is precisely the observed symptom: zero runners, pod running, no error anyone
+looks at. Clearing the PVC is what forces a real re-registration; the script prints the
+commands.
+
 ## Sequence — order matters
 
-1. **Get an Actions runner registered.** It is GitOps-managed
-   (`apps/wave-1/gitea-actions.yaml`, `apps/wave-1/gitea-actions-runner-secret.sops.yaml`),
-   so it is deployed but not registering — suspect a stale registration token in that
-   SOPS secret.
+1. **Get an Actions runner registered** — `runner-token-rotate.sh`, then clear the PVC so
+   the runner actually re-registers, then confirm it shows `online` in the API. Do not
+   skip the confirmation: the whole reason this went unnoticed is that a runner was
+   *recorded* as online without anyone checking.
 2. **Watch the gate actually report on a real PR**, and note the context name it produced.
 3. **Only then set `enable_status_check: true`** with that exact context.
 4. Add the human reviewer as a repo collaborator, then raise `required_approvals` to 1.

infra/gitea/runner-token-rotate.sh

@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+# Mint a fresh Gitea Actions registration token and write it into the SOPS secret.
+#
+# The token value is NEVER printed. It goes from the Gitea API into `sops set` and
+# nowhere else. (It is briefly visible in this host's process list as a sops argument;
+# acceptable on a single-operator workstation, and far better than echoing it.)
+#
+# This ALONE may not bring the runner back -- see "IMPORTANT" at the end of the output.
+set -euo pipefail
+HOST=gitea.home.keithjackson.dev
+SECRET=apps/wave-1/gitea-actions-runner-secret.sops.yaml
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+cd "$REPO_ROOT"
+[ -f "$SECRET" ] || { echo "not in the repo root, or $SECRET is missing" >&2; exit 1; }
+
+creds="$(printf 'protocol=https\nhost=%s\n\n' "$HOST" | git credential fill)"
+U="$(sed -n 's/^username=//p' <<<"$creds")"
+P="$(sed -n 's/^password=//p' <<<"$creds")"
+[ -n "$U" ] && [ -n "$P" ] || { echo "no stored git credential for $HOST" >&2; exit 1; }
+echo "==> minting an instance-level registration token as '${U}'"
+
+TOKEN="$(curl -sS --config <(printf 'user = "%s:%s"\n' "$U" "$P") \
+  "https://${HOST}/api/v1/admin/runners/registration-token" | jq -r '.token // empty')"
+[ -n "$TOKEN" ] || { echo "Gitea did not return a token" >&2; exit 1; }
+echo "==> got a ${#TOKEN}-character token (value not shown)"
+
+echo "==> writing it into ${SECRET} via sops"
+DEV_KUBECONFIG=/dev/null ./infra/devcontainer/dev.sh run \
+  sops set "$SECRET" '["stringData"]["token"]' "\"${TOKEN}\""
+unset TOKEN
+
+echo "==> done. Verify the file is still encrypted (no plaintext token):"
+grep -q 'ENC\[' "$SECRET" && echo "    OK - stringData is still SOPS-encrypted" \
+  || { echo "    REFUSING TO CONTINUE: $SECRET is not encrypted" >&2; exit 1; }
+
+cat <<'NOTE'
+
+Next: commit this on a branch, open a PR, and merge it so Flux applies the new Secret.
+
+IMPORTANT -- a new token is usually NOT sufficient on its own.
+act_runner registers exactly ONCE and then persists its identity in /data/.runner on the
+act-runner-data PVC. If Gitea no longer has a matching runner row (DB restore, the row was
+deleted, the instance was rebuilt), the pod starts, sees .runner, SKIPS registration, and
+polls with an identity Gitea does not recognise -- so it never appears in the runner list,
+which is exactly the observed symptom (zero runners, pod running).
+
+So after the Secret lands, force a genuine re-registration by clearing that state:
+
+    kubectl --context k3s-prod -n gitea-actions scale deploy/act-runner --replicas=0
+    kubectl --context k3s-prod -n gitea-actions delete pvc act-runner-data
+    kubectl --context k3s-prod -n gitea-actions scale deploy/act-runner --replicas=1
+
+(The PVC holds only runner registration state -- no build artifacts, nothing durable.
+Deleting it is the supported way to re-register. Flux recreates it from the manifest.)
+
+Then confirm it actually registered -- do not assume:
+
+    curl -s -u '<user>' https://gitea.home.keithjackson.dev/api/v1/admin/actions/runners | jq
+
+A runner must appear with status "online" and the labels ubuntu-latest / homelab.
+NOTE