Function synthesize_initial_component_values 

pub async fn synthesize_initial_component_values<C: XmtpSharedContext>(
    context: &C,
    mls_group: &MlsGroup,
) -> Result<BTreeMap<ComponentId, Vec<u8>>, BootstrapSynthesisError>

Synthesize the full AppDataUpdate payload set the bootstrap commit ships, keyed by ComponentId.

Sync parts delegate to xmtp_mls_common::app_data::migration::synthesize_canonical_subset_for_validation; the async part calls IdentityUpdates::get_association_state to partition failed_installations by owning inbox. Installations whose owner can’t be resolved are dropped — failed_installations is a retry-suppression hint, so each costs at most one extra retry.