Constant POSIX sh + jq script (embedded via include_str!) that applies the payload into ~/.claude, tracks ownership in state.json, never overwrites user-owned files, merges hook entries surgically, drives claude plugin and prints a JSON SyncReport. Also: settings.json kept 0600 (pre-flight N11), payloads containing symlinks are refused, slugs parsed via @tsv. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>