C-241 Wire runner deregistration through root module

The root (single-runner) module also uses termination-watcher but wasn't
wiring github_app_parameters through. Add enable_runner_deregistration,
github_app_parameters, and ghes_url to the root module's termination
watcher config, matching the multi-runner changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jensenbox

main.tf

@@ -381,6 +381,12 @@ locals {
     s3_bucket                 = var.lambda_s3_bucket
     tracing_config            = var.tracing_config
     metrics                   = var.metrics
+    enable_runner_deregistration = var.instance_termination_watcher.enable_runner_deregistration
+    github_app_parameters        = var.instance_termination_watcher.enable_runner_deregistration ? {
+      id         = local.github_app_parameters.id
+      key_base64 = local.github_app_parameters.key_base64
+    } : null
+    ghes_url = var.ghes_url
   }
 }
 

variables.tf

@@ -971,11 +971,12 @@ variable "instance_termination_watcher" {
       enable_spot_termination_handler              = optional(bool, true)
       enable_spot_termination_notification_watcher = optional(bool, true)
     }), {})
-    memory_size       = optional(number, null)
-    s3_key            = optional(string, null)
-    s3_object_version = optional(string, null)
-    timeout           = optional(number, null)
-    zip               = optional(string, null)
+    enable_runner_deregistration = optional(bool, true)
+    memory_size                 = optional(number, null)
+    s3_key                      = optional(string, null)
+    s3_object_version           = optional(string, null)
+    timeout                     = optional(number, null)
+    zip                         = optional(string, null)
   })
   default = {}