New York CCAP and HEAP: read the State Supplement Program after it merges #10239

PR #10158 adds ny_ssp, New York's State Supplement Program, and ny_ssp_living_arrangement. Two New York programs read SSI in ways that should now use them. Both changes depend on #10158 and belong in a separate PR after it merges.

1. Child Care Assistance Program (CCAP) should count the state supplement

• Rule. 18 NYCRR 404.5(b)(5)(vi): "Public assistance or welfare payments include public assistance payments such as ADC, SSI (including State supplemental payments), and home relief."
• Model now.
  • ny_ccap_countable_income counts adult ssi only.
  • parameters/gov/states/ny/ocfs/ccap/income/countable_income/sources.yaml has a comment saying PolicyEngine has no state supplement variable. That stops being true once Add New York state supplementation for 2026 #10158 merges.
• Change.
  • Count adult ny_ssp next to adult ssi in ny_ccap_countable_income, keeping the existing exclusion for a child's SSI. The OCFS compilation's 404.5(b)(6)(xxi) also excludes SSP received by a child.
  • Update the two comments.
  • Add two cases: a disabled adult SSI recipient whose ny_ssp is counted, and a child recipient whose SSP is excluded.
• Size. About one formula line. The family share is 1% of income above the poverty guideline with a $1-a-week minimum, so the effect is a few dollars a year. It could also move a family across the 85% SMI line at the margin.
• To check. The LII copy of 404.5 has the (b)(5)(vi) sentence but not the child exclusion in (b)(6)(xxi). The OCFS compilation (current as of 10/01/2023) and 23-OCFS-ADM-18 have both. Confirm the official 2026 text.

2. HEAP "Code A" categorical eligibility could read the state living arrangement

• Rule. 18 NYCRR 393.4(c)(1)(iii) makes categorically eligible "households, any member of which is in receipt of SSI as a couple or individual living alone (SSI Living Arrangement Code A)". The FY2026 State Plan describes it as the "state and federal living arrangement code of "A"".
• Model now. ny_heap_categorically_eligible approximates the state code A from SPM-unit membership.
• Change. Use ny_ssp_living_arrangement == LIVING_ALONE together with the existing federal own-household test. Add New York state supplementation for 2026 #10158 already leaves foster children and members living in a medical facility out of the living-alone count (18 NYCRR 398-4.5(a)(1)(vi)), so the current HEAP handling of foster children carries over. Add cases for a roommate household, a household with only a foster child, and an explicit living-alone determination.
• Size. A few lines. A code A unit is made up of SSI recipients, whose income usually passes the HEAP tests anyway, so the benefit effect is near zero.

Neither change creates a circular dependency. ny_ssp and ny_ssp_living_arrangement depend only on SSI variables and demographic inputs.

Raised in DTrim99's review of #10158 (Suggestion 3).