chart: add bootstrap job (v0.2.0)

Post-install/post-upgrade Job that calls /api/bootstrap on first deploy
and stores the admin API key in a Secret (<release>-admin-key by default).
Exits cleanly on subsequent upgrades when bootstrap is already complete.
Adds ServiceAccount, Role (secrets:create), and RoleBinding as hook resources.

charts/terdut-server/Chart.yaml

@@ -2,5 +2,5 @@ apiVersion: v2
 name: terdut-server
 description: A Helm chart for Terminal Duty — on-call alert management server
 type: application
-version: 0.1.0
+version: 0.2.0
 appVersion: "latest"