Task: Build the cross-gamma ladder

A party runs a cross-gamma ladder that names both factors of every pair and reads its figures from the sensitivity report, not from a file the engine does not write.

• The configuration sets ComputeGamma and lists the CrossGammaFilter pairs the ladder covers, and the ladder covers no pair outside that list.
• The ladder states that crossgamma.csv is unavailable at 1.8.17.0, so no reader waits for it.
• Every row names both factors and both shift sizes, and the pair is part of the stored key.
• A test proves the ladder has a row for each filter pair the run produced and no row for a pair it did not.

(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.

• Greek ladder reports — the design this task builds.
• ORE output formats — the sensitivity_report family and the pair columns the ladder reads.