Decide whether md_local_eitc belongs in the state EITC aggregator (taxsim_state_eitc)

External feedback flagged that `taxsim_state_eitc` / `state_eitc` omits `md_local_eitc` (~$273.60 in their reproduction).

`md_local_eitc` is a credit against Maryland's **county** income tax (subtracted in `md_local_income_tax_before_refundable_credits`), not the state tax, so its omission from a "state EITC" aggregator may be intentional. On the other hand, the aggregator's description says "All state Earned Income Tax Credits **and related credits**" and already includes broader credits such as `wa_working_families_tax_credit` and `mn_wfc`, and Maryland's local EITC is mandatory statewide.

Note the aggregator is reporting-only (TAXSIM compatibility): MD local tax liability already reflects the credit, so household net incomes are unaffected either way. Changing it would alter a partner-visible output, so this needs a deliberate decision rather than a drive-by fix.

Start by tracing the taxsim_state_eitc and state_eitc aggregators alongside md_local_eitc and md_local_income_tax_before_refundable_credits. Compare the aggregator description with Maryland’s local-tax treatment and the existing related-credit entries. Done means a deliberate, documented inclusion or exclusion decision that preserves the reporting-only scope and accounts for the partner-visible output.

Written by the indexing model from the issue text.