Story: Hold money exactly and move the external version on economic change

Hold every money quantity as an exact decimal, read the ORE boundary without loss, and derive the trade's external version from the economics actually held rather than from the reason a writer supplied.

• The ORE boundary reads money with a decimal parse from the document's own text, and no double crosses into the persisted domain.
• Every money quantity is exact decimal in the domain type and the column, with the C++ and SQL types agreeing by role across families.
• A trade carries an external version that moves when the economics held change, and does not move on a null amend or a non-economic change.
• An economic digest is computed over declared economic fields and folded from every instrument component up to the trade.

• Money is exact decimal and continuous is binary float. The list of what counts as money, and the one-way conversion rule, are Regime 2 criteria in Data-Oriented Design. Both halves are enforced by check-money-decimal-columns, each against its own baseline.
• The column scale is numeric(38, 12), not numeric(28, 12). Widening the scale alone narrows the integer part, and the suite caught it: three assertions failed with a numeric field overflow.
• The ORE binding carries the document's lexical form rather than only the parsed float, patched into generated code and re-applied by a script, because the generator is external and a regeneration otherwise drops the patch.
• The external version lives on the trade, not on an agreement, and the digest is a stored text column rather than a value computed on read, because the comparison that decides whether to bump needs the previous digest.
• The fold runs in C++ at the shared write choke point, through a trait the trading component specialises, because canonicalising a decimal is C++ and a second implementation in SQL would be a second digest.
• The digest covers declared economic fields only. A digest over the whole shape would move the external version for a description change, which is the failure the two-version rule exists to prevent.
• Verify the type work against the columns, never against the round trip: the exporter re-renders through ORE's float, whose shortest spelling restores the document's digits, so a truncated column still exports byte-identical text.

A scoreboard, so the story cannot read as done before it is. Evidence means something that was run, not something that was read.

Two of the five are done, three are partly done, and the row that matters most for the customer-facing claim is the last one: the mechanism is in and its component set is backwards. That is stated here rather than left to be inferred from task states.

• The per-field economic marking in the model, which would replace the name-based exclusion rule. Recorded as its own task because the rule in code works and the declaration is a codegen change.
• Enabling the external-version bump. It waits on the component set and on a reset of the stored digests, in that order.

• Exact Numbers and Economic Change — the rule, the measured boundary chain, and the evidence for each task below. This story is the plan; that page is the reasoning.