fix(poimen-frontend): correct secret key refs, remove unused NextAuth env

- LLM_OIDC_TOKEN_URL/CLIENT_ID/CLIENT_SECRET/SCOPE → all from poimen-secrets (correct keys)
- Remove NEXTAUTH_URL/NEXTAUTH_SECRET (app uses getServerToken(), not NextAuth)
- GOTIFY_TOKEN → poimen-secrets (key patched in-cluster)

k8s/apps/poimen/frontend-deployment.yaml

@@ -59,27 +59,22 @@ spec:
               valueFrom:
                 secretKeyRef:
                   name: poimen-secrets
-                  key: OIDC_TOKEN_URL
+                  key: LLM_OIDC_TOKEN_URL
             - name: LLM_OIDC_CLIENT_ID
               valueFrom:
                 secretKeyRef:
-                  name: poimen-oauth2-creds
-                  key: client_id
+                  name: poimen-secrets
+                  key: LLM_OIDC_CLIENT_ID
             - name: LLM_OIDC_CLIENT_SECRET
               valueFrom:
                 secretKeyRef:
-                  name: poimen-oauth2-creds
-                  key: client_secret
+                  name: poimen-secrets
+                  key: LLM_OIDC_CLIENT_SECRET
             - name: LLM_OIDC_SCOPE
-              value: "openid llm_inference"
-            # NextAuth
-            - name: NEXTAUTH_URL
-              value: "https://poimen.riotpiao.com"
-            - name: NEXTAUTH_SECRET
               valueFrom:
                 secretKeyRef:
                   name: poimen-secrets
-                  key: NEXTAUTH_SECRET
+                  key: LLM_OIDC_SCOPE
             # Gotify (server-side notifications + HITL messages)
             - name: GOTIFY_URL
               value: "http://gotify.notifications.svc.cluster.local"