refactor: unit testable units and cleaner dep injection

go/internal/network/repository.go

@@ -33,8 +33,6 @@ func newNetworkID() (networkID, error) {
 	return typeid.New[networkID]()
 }
 
-var errCapacityExceeded = errors.New("capacity exceeded")
-
 type repository interface {
 	create(ctx context.Context, name, adminHumanId string) (*Network, error)
 	getByID(ctx context.Context, id string) (*Network, error)
@@ -47,6 +45,9 @@ type repository interface {
 	getNetworksForHuman(ctx context.Context, humanId string) ([]*Network, error)
 	isMember(ctx context.Context, networkID, humanId string) (bool, error)
 	listAll(ctx context.Context) ([]*Network, error)
+
+	// listAllMemberships returns humanId -> networkIds for every human with at
+	// least one membership. Humans with zero memberships are absent from the map.
 	listAllMemberships(ctx context.Context) (map[string][]string, error)
 
 	// Invitations
@@ -233,9 +234,6 @@ func (r *repositoryImpl) isMember(ctx context.Context, networkID, humanId string
 	return isMember, err
 }
 
-// listAllMemberships returns humanId -> networkIds for every human with at
-// least one membership. Humans with zero memberships are absent from the map;
-// callers layer them in separately.
 func (r *repositoryImpl) listAllMemberships(ctx context.Context) (map[string][]string, error) {
 	rows, err := r.pool.Query(ctx, `SELECT human_id, network_id FROM network_members`)
 	if err != nil {