fix: restore in_pay for Section 54 OPC/OPO/OPT eligibility path

[mdiapenabc]

Section 54 legal auth codes short-circuit to Step 8, bypassing Step 7 in-pay restoration. Add a dedicated Step 8 transition so Not Eligible - In Pay and Not Eligible IP-TBD records return to In Pay when legal status is OPC, OPO, or OPT.

Description

records that were In Pay moved to Not Eligible - In Pay when legal status was temporarily end-dated (CRA cancellation). When legal status later changed to a Section 54 code (OPC, OPO, OPT), eligibility did not restore In Pay.

Section 54 codes short-circuit Step 2 → Step 8, bypassing Step 7 where in-pay restoration normally happens. Generic Step 8 only transitions Not Eligible - Out of Pay → Eligible TBD and leaves all other statuses unchanged.

This PR adds a Section 54–specific Step 8 path so Not Eligible - In Pay and Not Eligible IP-TBD return to In Pay when legal auth is OPC, OPO, or OPT. Other Step 8 callers (enroll TBD, placement/no-placement) are unchanged.

What changed

• Added step8_Section54Update with Section 54 transitions:
  • not_eligible_out_of_pay / null → eligible_tbd (unchanged)
  • not_eligible_in_pay / not_eligible_ip_tbd → in_pay (new)
• Step 2 routes OPC/OPO/OPT to step8_Section54Update instead of generic step8_UpdateEligibleTbd
• Unit and Step 2 integration tests for in-pay restoration and guard that generic Step 8 does not restore in-pay

How to test

• nvm use 24 && cd backend && npm test -- --run src/sync/eligibility/ passes
• Record In Pay → legal end-dated → Not Eligible - In Pay → legal updated to OPC/OPO/OPT → run eligibility → status returns to In Pay
• Same flow from Not Eligible IP-TBD → In Pay when legal auth is Section 54
• Section 54 record at Not Eligible - Out of Pay still transitions to Eligible TBD
• Non-Section 54 Step 8 path (enroll TBD, no placement) still leaves Not Eligible - In Pay unchanged