Function sync_all 

pub fn sync_all(home: &Path) -> SyncReport

(Re)write the canonical lean-ctx rules block into every detected agent config.

The source of truth is rules_canonical (via rules_inject::inject_all_rules), not .lean-ctx/rules.toml. Sync regenerates the canonical block and preserves the user’s own text around the <!-- lean-ctx-rules --> markers; rules.toml is consumed only by lint and produced by init (see super::config::RulesConfig). Stating this explicitly resolves the “sync doesn’t honor rules.toml” ambiguity — by design it does not (#548).