Accept Chronicle consumer_fact.v5 facts #1509

Problem

PolicyEngine/chronicle#377 merged on 2026-11-03 as 44eebe037. Since then Chronicle main writes every consumer fact as chronicle.consumer_fact.v5: the v4 row plus one optional top-level field, package_dimension_value_labels (dimension id, then value id, then text). That field holds a source package's own wording of a dimension value, and only where it differs from the label the row exports. dimension_value_labels and layout.groupby_value_label now carry the one label Chronicle registers for each value. Keys, values, constraints, periods and lineage do not change. v4's row schema has additionalProperties: false, so the new field needed a new contract version.

Microcosm declares Chronicle's consumer-fact row contracts only up to v4:

• microcosm.build.chronicle_epoch has CHRONICLE_CONSUMER_FACT_SCHEMA_VERSION_V4 as its newest row contract, so ACCEPTED_CONSUMER_FACT_SCHEMA_VERSIONS and consumer_fact_schema_epoch do not know v5. Chronicle's own table (CONSUMER_FACT_ROW_CONTRACTS in chronicle/epoch.py) now ends at v5.
• test_chronicle_epoch.py pins the accepted set at v1 to v4, and the shared artifact helper (test_support/microcosm_build/chronicle_feed.py) writes only v4 rows.
• No Microcosm code checks package_dimension_value_labels.

The loader carries each row's schema_version without checking it, and validate_chronicle_feed_pin compares the pinned versions and schema digest exactly with the artifact. Review round 1 of #1510 found that no code outside the tests reads the declared list, so a v5 feed would already load and the declaration on its own refuses nothing. The maintainer decided to enforce the list: a Chronicle feed pinned on a row contract Microcosm does not declare is refused. With that refusal, the next re-pin of any country's feed (UK, US, NZ or BE) onto Chronicle main needs v5 declared first. The UK feed has been re-pinned four times since 2026-10-24 for new packages.

Change

• Declare chronicle.consumer_fact.v5 beside v1 to v4. v1 to v4 keep loading.
• Refuse a feed pin, or a pinned artifact, that names a row contract the declaration table lacks: in the UK and US pin loaders, chronicle_feed_identity and validate_chronicle_feed_pin. A feed loaded without a full pin keeps carrying its per-row ids unchecked.
• Check the shape of package_dimension_value_labels where Microcosm checks dimension_value_labels: when a target is compiled from a fact, the field, if present, must map each dimension id to an object of value id to non-empty text, as the v5 schema says. Microcosm never reads the field as a label: each value keeps the label Chronicle exports.
• Tests use a v5 fact fixture validated against the real v5 schema, taken from Chronicle at 44eebe037.

No feed pin moves in this change. Re-pinning the UK feed onto Chronicle main is a separate pull request.

Follow-up

Once the US and Belgian feeds are on v5, the reviewed label choices for those countries in microcosm.calibrate.hierarchy_labels may no longer be needed. This change leaves them alone.