Audit round 9 lands: the location layer keeps its promises

Five blind reviewers over the day-old shelves layer, ~28 verified
findings — plus Eric's screenshot catching the biggest one live: the
generic .card is flex (built for review's photo-beside-ballot layout),
so unit headers shared a row with their grids and unshelved rows
flowed horizontally off the page. Shelf cards are now .card.stack.

The model fixes. Containment chains resolve recursively with a cycle
guard — minis inside an insert inside a big box live where the big box
does, instead of vanishing from every list; the stored-in endpoint
walks the whole chain when refusing cycles, and clears the newly
contained game's own shelf spot (one box must never consume capacity
in two openings). Contained games are listed residents but occupy no
shelf space: only physical boxes are stacked and fit-checked — the web
report now agrees with the dims report about the same opening. A
location pointing at a vanished opening (hand-edited or reverted
store) SURFACES as unshelved with a "shelf gone" chip in the app and
counts as homeless in the CLI, instead of hiding the game from every
list while the page declares everything has a home.

Honest edges. Opening dimensions are all-or-none everywhere (a
half-sized opening silently became limitless; the CLI report crashed
formatting it); a second grid on a unit continues the row letters so
labels stay unique and label-addressed CSV imports keep working, and
row letters survive past Z; CSV re-imports preserve hand-entered
notes; the ambiguity reject names the fix that actually works;
corrupt furniture/locations stores speak a 500 instead of a raw
traceback; the dims help text stops saying Kallax; DIM_AXES gets one
home in models.py instead of three drifting copies; the new stores
join CLAUDE.md's commit registry.

The page behaves. Custom-dims fields hide unless the custom preset is
chosen (typed values were silently discarded); the sheet is a real
dialog (role, aria-modal, Escape, focus return, one layer at a time);
backdrop close requires press AND release on the backdrop (a text-
selection drag out of the search box no longer dismisses); refresh
goes through changeGate and stops wiping the search mid-interaction;
the prompt() chain is an inline per-unit form with client-side
all-or-none validation; unit-create only toasts success after the
openings actually land, recovers from its own half-failures, and
guards against double-submit (a click retried against the re-rendering
DOM built a second grid — caught live in a Playwright run); warnings
speak (aria-labels on ⚠ and overfull in the fill bar's label);
unmeasured boxes are visible in cells and sheet rows; the library's
unshelved filter matches the Shelves page's definition; reorder
buttons have names; the detail locform wraps at phone width.

Eight new regression tests from the seats' sketches; 380 total.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016jXZFSTZQKzAC8fqpWSz9g

docs/guide.md

@@ -144,11 +144,11 @@ BGG's `0` means "never entered", not zero inches). Then:
 bggpipe dims
 ```
 
-reports coverage, the ten biggest footprints, and a fit check against an IKEA
-Kallax cube (13.2" × 13.2" opening, 15.4" deep) — listing every box that fits
-in **no** orientation, and every game whose dimensions can't be verified,
-because can't-verify is not the same as fits. Trusted dimensions also show on
-each game's Library detail page.
+reports coverage, the ten biggest footprints, and per-opening fit checks
+against your own furniture (see *Where everything lives*) — capacity,
+overfull warnings, boxes that fit in **no** orientation, and every game whose
+dimensions can't be verified, because can't-verify is not the same as fits.
+Trusted dimensions also show on each game's Library detail page.
 
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