Function initial_dictionary 

pub fn initial_dictionary(
    kind: InitialGroupKind<'_>,
    policy_set: &PolicySet,
    opts: &GroupMetadataOptions,
    creator_inbox_id: &str,
    group_root: Option<&GroupRoot>,
    catalogue: &[ApplicationComponentDefinition],
) -> Result<AppDataDictionary, MigrationError>

Build the complete dictionary stored in epoch zero. Collection values are stored snapshots, not proposal deltas. group_root is the root of a new keyed group, stored in GROUP_ROOT_KEY with its immutable registry entry; a restored placeholder passes none. No dictionary holds a COMMIT_LOG_SIGNER. catalogue is the client’s backend snapshot; only its eligible definitions enter the registry, and no component value is taken from it.