Ingest the staged UK UC deductions harvest (FRR, JRF floor, cap costings)

[vahid-ahmadi]

#21 staged and page-verified a full UC-deductions claim harvest at ~/scorecard-harvest/uk_deductions/ (CLAIMS.md collation, source PDFs alongside) and explicitly deferred DB ingestion as the handoff. Once the UK harvest→DB ingest path exists, land this family.

• Ingest the four claim families from UK UC deductions: external scores staged (FRR, JRF floor, historical cap costings) #21: Fair Repayment Rate (HMT AB2024, DWP Nov-2024 statistics, DWP/DfC screening, Policy in Practice), JRF protected-minimum floor (pre- and post-FRR variants), historical cap costings (Budget 2018/2020), Citizens Advice advances-to-grants
• Honor the hygiene notes verbatim: DWP quarterly deductions outturns → consumed_as_target, never external_scores; FRR fiscal rows benchmark against PSNCR only (no PSNB row exists to compare against); pre-/post-FRR JRF floors are distinct baseline_keys; floor rows are constructed/concept_mismatch until PE runs the floor jointly with benefit-cap interaction
• Attach the existing PE comparator (policyengine-uk#1815: 0.85m benunits, mean gain £421/yr vs DWP's £420) as the first result rows
• Register a uk-uc-deductions lane in data/lanes.json

🤖 Generated with Claude Code

[vahid-ahmadi]

Done — merged as #52 (stacked on #48).