Compare each target document with the set Lambda Feedback exported from it

[peterbjohnson]

Every ticket writes its tests before its code, and its pull request reports a run over a target set or a corpus folder with the number of flagged fields. See docs/plan.md.

A target is a folder holding one set: one questions document, an optional solutions document whose name ends in _solutions, and the folder Lambda Feedback exported for that set, named set_<Name>. Targets live under ExampleContents/targets/, either directly (targets/ME2_Fluids_introduction/) or grouped by course (targets/EART40013_Mathematical_Methods_II/CW1/, .../CW2/). The tool finds a target by its set_* folder. For each target, the tool converts the documents and compares the built set with the export through in2lambda's comparison function. Differences the maintainer has accepted are listed in a file beside the target's saved filter. The ticket is done when the ME2 target and the two EART40013 targets report their known differences and no other.

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Workbench ticket t40.

Live run over the three targets (manager, 2026-09-23 10:20)

EART40013_Mathematical_Methods_II/CW1: 28 differ, 0 known, 28 new, 1 flagged
EART40013_Mathematical_Methods_II/CW2: 18 differ, 0 known, 18 new, 3 flagged
ME2_Fluids_introduction: 21 differ, 0 known, 21 new, 2 flagged
3 targets, 67 new differences

All three targets are found and converted, and the structure of every one matches its export. The 67 'new' differences are almost all notation the comparison does not fold (spaces inside maths,  , \left(, separator rules); folding belongs in in2lambda's comparison (draft ticket 10). The real differences are the ones scored by hand this morning: CW1's answer-box pre-text and one OCR misread, ME2's separator minus signs.