BReg acceptance projects with no CI coverage and an incomplete artifact inventory

Found in the 0.28.0 pre-release review (2026-09-08). Line references are as of main after #926.

`products/breg/ACCEPTANCE-JOURNEYS.md` now lists all fifteen acceptance projects and what runs each. Two are run by nothing in CI: `household-history` (only `products/breg/scripts/test-historical-workflow.sh`, absent from every workflow) and `issuer-portability` (two `#[ignore]` tests reachable only through `products/breg/scripts/test-issuer-portability.py`, which no workflow invokes; the project has no `tests/` directory).

Related gaps found while mapping:
- `products/breg/contracts/artifact-inventory.yaml` omits six acceptance projects: `farmer-landholding-evidence`, `issuer-portability`, `person-name-change-rhai`, `person-registration-rhai`, `publicschema-household`, `registry-record-conformance`. No gate requires exhaustiveness.
- The `business`, `business-establishments`, and `inspection` projects' own `tests/journeys.yaml` files are executed by nothing; only the shared five-domain PostgreSQL test loads their sources.
- `products/breg/acceptance/farmer-landholding-evidence/tests/run-live.py` is invoked by nothing; its README tells a human to run it.
- `registry-record-conformance/tests/journeys.yaml` is empty (`journeys: []`); its real proof is `postgres_record_profile_conformance.rs`.

Proposed change: either wire the two uncovered projects into a CI job (the postgres lane or a scripts job) or mark them maintainer-only in the acceptance matrix; make `validate_product.py` require every `products/breg/acceptance/*` directory to appear in `artifact-inventory.yaml`; decide whether per-project `journeys.yaml` files that nothing executes should be run by `bregctl test` in the postgres lane or removed.

Start with products/breg/ACCEPTANCE-JOURNEYS.md, products/breg/contracts/artifact-inventory.yaml, and validate_product.py, then inspect workflows invoking the listed scripts and tests. Trace coverage for household-history, issuer-portability, farmer-landholding-evidence, and the per-project journeys.yaml files. Done means the chosen CI or maintainer-only policy is represented, artifact inventory validation is exhaustive, and the relevant acceptance checks are executed or explicitly excluded.

Written by the indexing model from the issue text.