feat: add runner conversion scripts and strengthen cutover automation

runners-conversion/augur/.env.example

@@ -0,0 +1,12 @@
+# .env — Shared configuration for all runner containers.
+#
+# Copy this file to .env and fill in your values:
+#   cp .env.example .env
+#
+# This file is loaded by docker-compose.yml and applies to ALL runner services.
+# Per-repo settings (name, labels, resources) go in envs/<repo>.env instead.
+
+# GitHub Personal Access Token (classic or fine-grained with "repo" scope).
+# Used to generate short-lived registration tokens for each runner container.
+# Never stored in the runner agent — only used at container startup.
+GITHUB_PAT=ghp_xxxxxxxxxxxxxxxxxxxx