# U7 is three-quarters built and blocked on one word

_2026-09-22 · booth_

**The last v1 unit, decomposed by what the operator has already ratified versus
what he has not.** ROADMAP's U7 row names four components. Three were already
approved there and are **built, tested and deployed** (`a306e2d`). The fourth is
a scope departure and is **deliberately not built**.

| component | ROADMAP | state |
|---|---|---|
| sticky rail | ratified | **landed** — totals + per-filter counts |
| filters | ratified | **landed** — all / flagged / annotated / unanswered |
| grid keyboard | ratified | **landed** — `←/→ f n Enter Esc`, bound only when a grid exists |
| **sections → filename groups** | **departs** | **NOT BUILT** |

`tests/test_navigation.py::test_no_group_rail_is_shipped_yet` fails the moment
somebody builds the group rail anyway, so the departure cannot arrive by
accident while the ruling is outstanding.

## The question, and why it is his

**Drop subfolder sections for filename-prefix groups — yes or no?**

Measured (see [[2026-09-22-u7-remeasured-before-scoping]]): **zero of eleven
gallery booths have a subdirectory**, so sections buy nothing; stripping a
trailing digit-run from the stem yields **5–16 sensible groups on four of the
five large galleries** and degenerates to one group on the fifth. The
replacement is better on the evidence — but swapping a ratified component for
an unratified one is scope direction, not implementation.

Contract at `docs/contracts/u7_navigation.contract.md`, status
`PARTIALLY LANDED`, with the departure named as the operator's call.

## Decisions taken under stated assumption, both cheap to reverse

- **`unanswered` means HAS AN OPEN PICK** — the U4 hold predicate, which already
  exists. The other reading ("has no mark at all") is a genuinely different
  question and stays an open question on the contract.
- **Filters are LINKS, not scripts**, resolved server-side, so the gallery keeps
  working with JavaScript off. U3 cost the verbatim path its no-JS operation and
  said so plainly; the gallery is the surface the operator actually reviews on,
  and this unit does not repeat it there.

## The vacuous falsifier, written an hour after the entry about them

`test_filtering_never_reorders` compared each filtered view against the
**unfiltered response** — so a mutation reversing the order reversed both sides
and it **stayed green under the exact change it forbade.** Caught only by
running the mutation rather than trusting the assertion.

Rewritten against an independent truth: U1 INV-3 says the order IS `sorted(rel)`,
so each view must be sorted, full stop, with no reference to another response.
Re-verified RED. **Every new falsifier in this session was mutation-checked
after this**, and that is the practice to keep — see
[[2026-09-22-vacuous-falsifiers]].