I got it. The account mapper’s parameter was wrong.
I’ve changed the problematic code:
app.accountMapper = auth.NewAccountMapper(
cdc,
app.keyAccount, // target store
auth.ProtoBaseAccount, // prototype
)
to this:
app.accountMapper = auth.NewAccountMapper(
cdc,
app.keyAccount, // target store
func () auth.Account {
return &types.AppAccount{}
},
)
So, now I can see Bob’s balance!
Hope it helps someone.