Feature idea: readiness check only true when at least one source connected and data is flowing

Code:

https://github.com/flashbots/mempool-dumpster/blob/b235d6737ffe97cff22b722db3fc97c3f237634e/collector/collector.go#L140-L144

Start at collector/collector.go lines 140-144 and trace how readiness is currently determined. Identify how source connections and incoming data are represented, then define the readiness behavior so it is true only when at least one source is connected and data is flowing. Done means the readiness check reflects that condition.

Written by the indexing model from the issue text.