Add shared cost allocation reporting

README.md

@@ -24,6 +24,7 @@ uv run finhub runway --balance 12000 --monthly-burn 2100,2200,2000
 uv run finhub ledger import cloud tests/fixtures/cloud-costs.csv
 uv run finhub ledger set-price --client acme --application portal --instance prod-01 --period 2026-07 --amount 100 --source agreement-2026-01
 uv run finhub ledger margins
+uv run finhub ledger allocations
 uv run finhub evaluate
 uv run finhub evidence --seed-fixtures
 uv run finhub serve
@@ -68,6 +69,15 @@ allocations, optimization cases, and commitment candidates outside booked
 spend. `ingest_resource_forecast` adapts resource-control's v0.1 monthly backup
 forecast without inventing resource identity.
 
+Shared-infrastructure allocation remains authoritative in resource-control.
+Fin-hub's `ledger allocations` command consumes current `AllocationEvidence`,
+requires every referenced financial fact to be current and uniquely claimed,
+checks period/environment/currency and booked totals, and calculates target and
+residual amounts in integer minor units. The producer-supplied versioned method
+and provenance remain visible. Deterministic largest-remainder rounding makes
+all target amounts plus the explicit unattributed residual reconcile exactly
+to booked cost.
+
 ## Related Workplans
 
 - `the-custodian/workplans/CUST-WP-0025-fos-hub-bootstrap.md` — umbrella