Remove external OIDC configuration for internal auth

Removed all Pocket ID OIDC environment variables. OpenCloud now uses
its internal IDP for authentication instead of external OIDC provider.

The frontend config.json now correctly points to the internal IDP:
- Authority: https://opencloud.basicstack.de (was: auth.basicstack.de)
- Client ID: web (internal IDP client)

This fixes the login redirect issue where users were being sent to
the login page but couldn't see the login form.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/opencloud/opencloud-deployment.yaml

@@ -138,36 +138,6 @@ spec:
               name: opencloud-config-secrets
               key: admin-user-id
 
-        # OIDC Configuration (External IDP - Pocket ID)
-        - name: OC_OIDC_ISSUER
-          value: "https://auth.basicstack.de"
-        - name: OC_OIDC_CLIENT_ID
-          valueFrom:
-            secretKeyRef:
-              name: opencloud-oidc-secret
-              key: oidc-client-id
-        - name: OC_OIDC_CLIENT_SECRET
-          valueFrom:
-            secretKeyRef:
-              name: opencloud-oidc-secret
-              key: oidc-client-secret
-        - name: OC_OIDC_CLIENT_SCOPES
-          value: "openid profile email groups offline_access"
-        - name: PROXY_OIDC_REWRITE_WELLKNOWN
-          value: "true"
-        - name: PROXY_USER_OIDC_CLAIM
-          value: "email"
-        - name: PROXY_USER_CS3_CLAIM
-          value: "username"
-        - name: PROXY_AUTOPROVISION_ACCOUNTS
-          value: "true"
-        - name: PROXY_ROLE_ASSIGNMENT_DRIVER
-          value: "oidc"
-        - name: PROXY_ROLE_ASSIGNMENT_OIDC_CLAIM
-          value: "groups"
-        - name: IDP_DOMAIN
-          value: "auth.basicstack.de"
-
         # SMTP Configuration
         - name: NOTIFICATIONS_SMTP_HOST
           value: "mail.basicstack.de"