ROADMAP's U7 row names four components. Three of them -- a sticky rail,
filters, and grid keyboard -- are already ratified there and are implemented
here. The fourth, replacing directory sections with filename-derived groups, is
a scope DEPARTURE the operator has not ruled on and is deliberately not built;
test_no_group_rail_is_shipped_yet fails the moment somebody builds it anyway,
so it cannot arrive by accident while he is away.
Filters are links carrying a query parameter, resolved server-side, so the
gallery keeps working with JavaScript off -- U3 already cost the verbatim path
its no-JS operation and said so, and the gallery is the surface the operator
actually reviews on. An unknown filter falls back to `all` rather than indexing
a dict by a value that arrives from an operator-editable URL.
`unanswered` means HAS AN OPEN PICK, the U4 hold predicate that already exists.
The other reading is a real and different question and stays open on the
contract rather than being guessed at.
Filtering is a VIEW and never reorders. The grid renders `sorted(rel)` with
non-matching items removed, so "the third one" means the same thing with a
filter on as with it off, and the zoom ring is untouched by any filter -- a
ring that changed with the grid would make `next` depend on how the operator
arrived, which is the misfiled-judgment failure invariant 6 exists for.
⚠ The first version of that invariant's test was VACUOUS and the mutation run
caught it: it compared each filtered view against the unfiltered RESPONSE, so a
reversing mutation reversed both sides and it stayed green under the exact
change it forbade. Rewritten against an independent truth -- U1 INV-3 says the
order IS sorted(rel) -- and re-verified RED. Written an hour after the entry
describing this exact failure class, which is worth recording.
611 -> 623 tests.