The deploy hydration created dex-sizer-client with wrong value.
Reverting to the original shared secret that sizer expects
(73eda906... - active for 81 days before hydration overwrote it).
Changes:
- sizer-oidc-client: restore correct shared secret
- dex-sizer-client: add managed manifest to prevent future drift
- dex.yaml: add manifests source for ArgoCD to sync the secret
Broken by stacks rehydration pipeline run.
