Function validate_component_integrity 

pub fn validate_component_integrity(
    components: &[Value],
    spec: &RefFieldSpec,
    root_id: &str,
    allow_dangling_references: bool,
    allow_missing_root: bool,
) -> ValidationReport

Validate component integrity: duplicate ids, missing root, dangling references. Collects ALL errors (does not short-circuit), returning a ValidationReport.

allow_dangling_references skips the dangling check entirely (incremental update refs may live elsewhere). allow_missing_root skips the missing-root check.