feat(infra): implement multi-environment deployment strategy

- Update CD workflow for branch-based environments (main -> Prod, dev -> Dev)
- Support Terraform workspaces for environment isolation
- Add manage_runtime_secrets flag to prevent accidental secret destruction
- Add infra management and secret setup utility scripts
- Prefix GitHub deployer identity with environment name
- Synchronize bot environment variables with latest runtime config

infra/terraform/modules/cloud_run_service/main.tf

@@ -54,6 +54,12 @@ resource "google_cloud_run_v2_service" "this" {
     percent = 100
     type    = "TRAFFIC_TARGET_ALLOCATION_TYPE_LATEST"
   }
+
+  lifecycle {
+    ignore_changes = [
+      template[0].scaling,
+    ]
+  }
 }
 
 resource "google_cloud_run_v2_service_iam_member" "public_invoker" {