render() is pure and gives every file the header (bodies arrive per task).
apply() runs one at a time, debounces requestApply, writes changed files
atomically (mode 0640), keeps .prev, sends each needed reload once, skips
pjsip reload and sets restartRequired when transports change, and records
generator_runs. AMI connects on startup and every reconnect forces a full
apply. Admin routes: config apply/rollback and a masked generated-files view.
Task: M2-T2
iamdoubz