fix(association): a figure counted as none comes off the band

[ExtraToast]

What

The number band leaves out a figure the api counted as zero. Found while checking main's renders: /membership read 0 Events in the past year, because the dev database holds no events at all and /statistics/association answers eventsLastYear: 0.

Why not the floor

FLOORS already covers the case where the api has not answered — the page stands on a number the association publishes about itself and marks it 20+. A counted zero is a different thing: it has been counted, and printing 20+ there would be a claim the api has just contradicted. So the figure comes off the band rather than falling back.

The band now draws what it is given rather than a fixed four; the grid closes up around the gap.

Checks

254 unit tests across the association domain and the pages pass, including two new cases: a figure counted as none is left out, and one nobody has counted yet keeps its floor. Verified live — the band shows 200+ Members, 11 Esports teams this season, 16 Member-run committees, with the zero gone.

The membership e2e suite passes 24/25; the failure is does not animate the pitch in for a visitor who asked for less motion, which fails identically on stock main and is what #1151 is open for.

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Diff breakdown — █ added ░ removed, scaled to the largest row.

frontend                                           +33     -6    3
  production         ██████████████████░░░░░░░░    +14     -6    2
  unit tests         █████████████████████████     +19     -0    1

──────────────────────────────────────────────────────────────────
production                                         +14     -6
tests                                              +19     -0  1.36 test lines per prod line
total (hand-written)                               +33     -6  3 files