feat(monitoring): alert when the keycloak passkey reconciler's Job fails

KeycloakPasskeyReconcilerFailing (warning, for 15m) on
kube_job_status_failed{namespace="keycloak", job_name=~"keycloak-passkey-reconciler-.*"},
following the sibling client-secret reconciler's rule. promtool unit tests pin it in
both directions: quiet when succeeding, firing after 15m on a failed Job, quiet on the
SIBLING's failure, and quiet on a single transient failure. Runbook added and projected
by the runbooks ConfigMap generator.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

runbooks/README.md

@@ -141,6 +141,8 @@ Each affected runbook says so on its own page and gives the by-hand equivalent.
 - **`keycloak-db`** — Keycloak's CloudNativePG database is unavailable.
 - **`keycloak-client-secrets`** — the client/URL reconciler failing or silent. The 2026-09-06 lockout that
   every green signal missed.
+- **`keycloak-passkey-reconciler`** — the passkey policy / enrolment action / browser-flow reconciler
+  failing. Never writes the flow you log in through; a missing `CONFIGURE_TOTP` is the cause that bites.
 - **`oauth2-proxy-auth-failures`** — a gated app "is up but does not work". Linked from
   `OAuth2ProxyGateUnobserved`. The gate answers an unauthenticated **XHR** with a 302 to Keycloak
   rather than a 401, the browser follows it silently against a live SSO session, and the call