Adds missing CLIENT_SECRET env injection + nodeSelector constraint:
- k8s/argocd/bootstrap/forgejo.yaml: inject GITEA__oauth2__CLIENT_SECRET
from forgejo-oidc Secret (created by authentik-provision Job), and pin
pods to talos-cp-1 via nodeSelector (only node with Longhorn storage —
gitea-shared-storage PVC can't attach on cp-2/cp-3)
Root cause chain for 'Forgejo SSO not working':
1. Authentik 2026.5.5 requires explicit grant_types on OAuth2 providers
2. Old provision script never set it → all providers had grant_types=[]
3. /authorize returned 'Invalid grant_type for provider' → all SSO broken
4. Fixed in k8s/security/iam/scripts/authentik-provision.py (commit be2a56c)
+ successfully re-ran via iam-jobs Application sync
5. But Forgejo deployment still missing CLIENT_SECRET env var → no creds
6. Forgejo bootstrap App used inline valuesObject (chicken-egg with git
repo self-hosting), but missing the extraEnv block that was only in
k8s/security/ci-cd/forgejo-values.yaml → CLIENT_SECRET never injected
All 4 OAuth2 providers now have correct grant_types=['authorization_code',
'refresh_token'], Forgejo pods now have CLIENT_SECRET env, and pods are
constrained to the storage node. SSO login flow should now work end-to-end.
