feat(apps): add Authentik to one-click app catalog

[chbndrhnns]

Adds Authentik (version 2026.8.1) to the OpenShip 1-click app catalog.

Summary of changes

• Adds packages/core/src/apps/catalog/authentik.json configuring:
  • postgresql (postgres:16-alpine) with healthcheck and persistent volume
  • redis (redis:alpine) with healthcheck and persistent volume
  • server (ghcr.io/goauthentik/server:2026.8.1) exposing port 9000
  • worker (ghcr.io/goauthentik/server:2026.8.1)
  • Auto-generated secrets for POSTGRES_PASSWORD and AUTHENTIK_SECRET_KEY
  • Connection outputs for the main URL and initial setup wizard (/if/flow/initial-setup/)
  • Declares minEngine: "0.6.6" for commandArgv compatibility
• Regenerates packages/core/src/apps/catalog.json
• Adds the Authentik mark in apps/dashboard/src/components/AppLogo.tsx

Closes #856

Validation

• bun test packages/core/src/apps/catalog.test.ts passes (28/28)
• bun test apps/dashboard/src/components/app-logo.test.ts passes (2/2)
• Successfully deployed and verified against OpenShip.