Task: ORE export drops required elements from 17 example documents

The import to export round trip over external/ore/examples/Products/Example_Trades is lossy for 17 of the 132 documents. The walk writes all 132 and reports no skips, but the exported document is missing a child element the schema requires, so it cannot be read back. One trade per affected document is lost.

The failures are not scattered. They cluster in the Commodity, Credit, FX worst-of and Exotic product mappers, and each one drops a different required element:

The two risk participation agreement documents were listed here. The credit rework fixed them: the agreement now stores and exports its protection fee, its underlying and its participation rate, and both documents re-read.

Run of 2026-09-26 over the 132 documents:

• Every document the walk writes under external/ore/examples/Products/Example_Trades whose dropped element has a field in the domain instrument can be read back, so known_export_gaps() in xml_exporter_directory_roundtrip_tests.cpp shrinks to the five documents whose value the domain does not hold.
• A value the export now writes comes from the domain instrument and is not invented: what the reverse mapper writes, the forward mapper reads.
• No document that already re-read stops re-reading.

(Implementation strategy. Written when work starts; key decisions are distilled into the parent story's * Decisions at close, but the plan itself stays — it is the historical record of what we did.)

Every number this task claims about a tree, with the command that produced it and the commit it was measured at. A number without both is not a measurement, because a clean-up record describes a tree and trunk moves under a branch: a consumer count, a gate's component count and a suite's size all change with no code changing, and the reader of a bare number cannot tell which tree it came from. Where the raw output matters, put it in an evidence/ file beside the task and name that file in the Command column.

Manual QA scenarios (scaffolded via compass add test_scenario) that verify this task. Link new ones here as they're created; the scenario doc itself links back via its "Verifies task" field.

The documents that fail to re-read fell from fourteen to five. Nine now round trip: the six commodity documents, the equity TaRF, and the two performance options. Each fix carries a value the domain holds — a commodity leg's quantity, the swaption's fixed price, the TaRF's knock-out level, and the performance option's strike prices.

The five that remain each need a value the domain instrument does not hold, so closing them means changing the domain, not the mapper. That work has its own task, which the story now carries.

Acceptance met: the nine documents whose dropped element has a domain field re-read, every value written comes from the instrument, and no document that already re-read stopped re-reading.

Captured 2026-09-26 in the product backlog; promoted preserving the UUID.