fix(platform): use apps-core layer (apps-stateless not in allowed set)

[jorisjonkers-dev-agents]

The homelab-deploy Compose Gate rejects apps-stateless — the allowed layers are: apps-core, apps-vso-secrets, apps-metallb-config, apps-data, apps-mail, apps-observability. Switches deployment.yml to apps-core, matching agents-ui.

[github-actions]

Deploy Preview — auth-ui

Environments: production
Context ref: ghcr.io/jorisjonkers-dev/cluster-deploy-context-public@sha256:64d00fe03a271dbd03a48005d0a0cc6cc5fe43df23c0e97b649c2f8b3e78b418
Workloads: 1 | Routes: 1 | Gatus entries: 0

Image refs

• auth-ui: ghcr.io/jorisjonkers-dev/auth-ui@sha256:0000000000000000000000000000000000000000000000000000000000000000

SC-11 Readiness Scorecard

	Check	Status
✅	schema_pinned	pass
✅	context_pinned	pass
✅	no_latest_images	pass
✅	health_declared	pass
✅	route_owner_authmode_declared	pass
✅	rollback_retention_acknowledged	pass
❌	no_raw_secrets	fail
➖	stateful_policy_declared	not_applicable
➖	raw_manifests_guarded	not_applicable
❌	npm_signatures_verified	fail

⚠️ Escape hatch in use: one or more scorecard checks are not_applicable.

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Updated by deploy-preview action on push to this PR.