LCFS consumption with NEED raking, ETB VAT, and ETB services/NHS stages

[juaristi22]

Workstream E6 of the UK-migration master epic #665; child of #145. May split into consumption / VAT+services children at review time (they share only the ETB artifact pins).

Scope

• LCFS consumption QRF (18 outputs: 12 COICOP divisions, petrol/diesel, bus fares, domestic/electricity/gas energy); the has_fuel seeded flag plus the WAS-bridge QRF; petrol/diesel zeroed for non-ICE households.
• NEED energy raking: 50-iteration iterative proportional fitting over four margins (gross-income band, tenure, accommodation type, region), run on the training frame and again post-imputation — as a generic iterative_proportional_fit operation. The NEED 2023 kWh tables and Ofgem unit rates become declared anchors with citations (today they are hardcoded literals in the incumbent's consumption.py), each flagged chronicle_candidate where a future fact family could carry them.
• ETB VAT QRF (full_rate_vat_expenditure_rate; VAT rates read from the parameter tree, not literals).
• ETB services QRF (education / rail-subsidy / bus-subsidy spending) + NHS person-level allocation from the age-gender table + the rail_usage derivation (subsidy ÷ fare index, so reforms can move the index independently).
• The incumbent's post-calibration rail/bus/fuel aggregate scalers are explicitly out of scope here — they run after weights exist and are adjudicated on Calibrate the UK national build from Ledger-backed targets #623 (re-express as calibration targets where chronicle families exist, else a D-side post-calibration stage with a mass-change record).

Acceptance

• Weighted totals per output family within stage tolerance vs the licensed register; deltas published SDC-safely.
• NEED/Ofgem anchors declared with citations in the manifest; aggregate_admin gate declared for the anchored families.
• Determinism per the WS-E harness; declaration-lockstep tests.

UK-specificity note (required in the PR)

LCFS/ETB column semantics and the NEED margins are UK; QRF fitting, IPF raking, and support clips should be generic operations. List anything beyond that and why.

Depends on: E5 (num_vehicles predictor).