config(authentik): upgrade to 2025.10.3, remove Redis dependency

Authentik 2025.10 no longer uses Redis for caching/sessions (now uses
Postgres). Updated stack to remove Redis config and renamed deprecated
WORKER__CONCURRENCY to WORKER__THREADS. Redis DB 0 now available.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

stacks/authentik.yml

@@ -9,7 +9,7 @@ version: '3.8'
 
 services:
   authentik-server:
-    image: ghcr.io/goauthentik/server:2024.8.4  # Pinned version (2024.10 has redirect loop issues)
+    image: ghcr.io/goauthentik/server:2025.10.3  # Pinned version (2024.10 has redirect loop issues)
     container_name: authentik-server
     restart: unless-stopped
     command: server
@@ -33,11 +33,6 @@ services:
       AUTHENTIK_POSTGRESQL__PASSWORD: F//j0ktck7cX06Vfgh0YXceONOtlSsHvadqROICeDx8=
       AUTHENTIK_POSTGRESQL__USE_PGBOUNCER: false
 
-      # Redis (shared)
-      AUTHENTIK_REDIS__HOST: redis-shared
-      AUTHENTIK_REDIS__PORT: 6379
-      AUTHENTIK_REDIS__DB: 0
-
       # Secret key (generated: openssl rand -base64 32)
       AUTHENTIK_SECRET_KEY: TnFaTZ//RDcO2hxVR4QGOBORd5tfXe4Vok+lcAz/AdE=
 
@@ -79,7 +74,7 @@ services:
           memory: 256M
 
   authentik-worker:
-    image: ghcr.io/goauthentik/server:2024.8.4  # Same version as server
+    image: ghcr.io/goauthentik/server:2025.10.3  # Same version as server
     container_name: authentik-worker
     restart: unless-stopped
     command: worker
@@ -106,7 +101,7 @@ services:
 
       # Worker-specific configuration
       AUTHENTIK_BOOTSTRAP_WORKERS: 1   # Single worker (homelab scale)
-      AUTHENTIK_WORKER__CONCURRENCY: 2  # 2 threads per worker
+      AUTHENTIK_WORKER__THREADS: 2  # 2 threads per worker
 
     volumes:
       - /home/jpmschweitzer/docker-data/authentik/media:/media
@@ -136,7 +131,7 @@ services:
           memory: 128M
 
   authentik-proxy:
-    image: ghcr.io/goauthentik/proxy:2024.8.4  # Standalone outpost (embedded outpost not working in 2024.8.4)
+    image: ghcr.io/goauthentik/proxy:2025.10.3  # Standalone outpost (embedded outpost not working in 2024.8.4)
     container_name: authentik-proxy
     restart: unless-stopped
     environment: