Task: Round trip the sensitivity configuration

Sensitivity shares the shift vocabulary with stress, so this task proves the shared shape against a second file rather than a second design.

• Every sensitivity.xml in the corpus imports, exports and matches.
• All twenty-six families present in the corpus round trip, including the ones with no example file today.
• The distinction between a shift block and a per-point override survives the round trip.

(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.