chore(comfyui): retire the app for good

comfyui served nothing and its oauth2-proxy could not start: the Secret
carried only client-secret while the Deployment asked for client-id,
cookie-secret and client-secret. Rather than repair a service nobody used,
remove it from every layer.

Gone:
  - k8s/apps/comfyui/* and its ArgoCD Application
  - the cloudflared tunnel rule for comfyui.riotpiao.com
  - the CoreDNS rewrite in the terraform Corefile (the tracked source)
  - the Cloudflare DNS record (terraform tfvars)
  - the ZITADEL OIDC app and its two rotation tables
  - the KeyRotation object

Not gone by this commit: the comfyui namespace and its 50Gi PVC. ArgoCD does
not own either, so a person deletes both by hand after the prune. The local
cluster-config/talos-*.yaml copies are gitignored; they carry the same
removal and need an apply-config to reach the live CoreDNS.

k8s/apps/llm-serving/qwen-cpu.yaml

@@ -1,5 +1,6 @@
 # qwen2.5:3b-instruct on CPU (talos-cp-2, 144GB RAM, 24 cores).
-# Moved off GPU to free a V100 for ComfyUI. Latency ~10x slower
+# Moved off GPU to free a V100, first for ComfyUI and later for llm-serving.
+# Latency ~10x slower
 # than GPU but sufficient for lightweight tasks (summarization,
 # classification, quick answers).
 apiVersion: apps/v1