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]>

platform/monitoring/alerts.yaml

@@ -1445,6 +1445,36 @@ spec:
               redirect-URI drift would go uncorrected and unnoticed (docs/15). This is the rule
               that would catch the healer being quietly absent during a domain migration.
             runbook_url: "https://${BASE_DOMAIN}/runbooks/keycloak-client-secrets"
+        # --- The passkey reconciler (platform/keycloak/passkey-reconciler.yaml) ---
+        # The sibling CronJob that converges the WebAuthn passwordless policy, the passkey
+        # enrolment required action, and the browser login flow (blue/green; bound only when
+        # git's bind-browser-flow is "true"). There is no failure that is "expected by
+        # design": with the bind switch off, an unbound verified candidate is a SUCCESSFUL
+        # run. So a failed Job is always news — drift it may not repair (e.g. a missing
+        # CONFIGURE_TOTP, which locks every platform-admin out), a built flow that did not
+        # verify, an exhausted candidate-alias budget, or an admin API it cannot reach.
+        # backoffLimit is 0, so one failed tick is one failed Job; `for: 15m` waits out a
+        # single transient failure while still firing within about two ticks.
+        # A separate rule from the client reconciler's on purpose: different CronJob,
+        # different job_name, different runbook — one cause, one alert.
+        # UNVERIFIED-ON-CLUSTER at authoring time: the CronJob had never run, so its series
+        # did not exist yet. The metric and label are the ones the sibling rule above uses.
+        - alert: KeycloakPasskeyReconcilerFailing
+          expr: |
+            max(kube_job_status_failed{namespace="keycloak", job_name=~"keycloak-passkey-reconciler-.*"}) > 0
+          for: 15m
+          labels:
+            severity: warning
+          annotations:
+            summary: "Keycloak passkey reconciler failing"
+            description: >-
+              A keycloak-passkey-reconciler Job has been failing for 15m. The realm's passkey
+              policy, the passkey enrolment action or the browser login flow may differ from
+              git, or a default required action (CONFIGURE_TOTP) may be missing. The reconciler
+              never writes the flow users are logging in through, so a failure here does NOT
+              by itself mean login is broken. Read the Job log: every PROBLEM line names the
+              pass and the exact divergence.
+            runbook_url: "https://${BASE_DOMAIN}/runbooks/keycloak-passkey-reconciler"
 
 # =====================================================================================
 # The monitor's own capacity — don't let the monitor blind itself (docs/10)