nix-cache: remove unused Gitea Actions runner

The actions runner on nix-cache01 was never actively used.
Removing it before migrating to nix-cache02.

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

terraform/vault/variables.tf

@@ -46,12 +46,6 @@ variable "cache_signing_key" {
   sensitive   = true
 }
 
-variable "actions_token_1" {
-  description = "Gitea Actions runner token"
-  type        = string
-  sensitive   = true
-}
-
 variable "homelab_deploy_listener_nkey" {
   description = "NKey seed for homelab-deploy listeners"
   type        = string