[plainprogrammer]

Implements spec 040 (v0.2.2) following its plan. A collector picks one of their locations for the scanner sitting, and every card added afterwards goes into the lot of that printing and finish in that place. The place can change mid-sitting (later adds only), survives a reload, and goes when the sitting ends. An account with no locations sees the scanner exactly as before. Nothing changes in the export.

What each phase did

Phase	Commit	What
1	31a9a0a	scanner_sittings.location_id, nullable and indexed, REFERENCES locations ON DELETE SET NULL. Added by a raw ADD COLUMN outside a transaction (the lots migration's pattern), so no table is copied and no entry is lost. A migration spec proves down/up keeps every sitting and entry (AC-6.0).
2	e4bedff	Scanner::Sitting.add! reads the place inside its transaction and adds through Lot.add!(location:). Sitting.place! opens, sets, clears or drops the sitting. #pointless? implements P1's narrower rule. kept_entries preloads each lot and its location.
3	35b0339	PATCH /scanner/sitting with sitting[location_id] answers with a Turbo Stream that redraws the panel. The location is looked up through Current.account.locations: a bad value is a 422 with decision 7's alert, a missing key a 400. The picker appears in the panel, alone when no sitting is open, and under the Done summary. The add notice names the entry's lot's place.
4	43d462c	The panel: "This sitting: N cards, in Blue binder", "in " on each entry, and the three empty-sitting copies. Scanner.md is updated.
5	7a6256a	Headless Firefox flows: choose, scan, change, reload, clear, Done, keyboard only, and a 360px frame with a long name. The 360px example found two overflows, fixed here (see below).
6	d259770	The collection-and-lots area doc, the roadmap (21a built, run before the spikes by ruling) and the specs index (supersessions of 009 and 032, both directions).
Evidence	e286815, f392321	Screenshots and GIF; verification.md with per-AC evidence and the implementation review.
Review fixes	27862c7	See the review section.
Wrap	1c1ab63, 9a4ded9, 2649e4b, 7aa45a1	A lesson (long names in narrow checks), the distillation into collection and lots and data portability, the frozen line, and the distillation record.

Rulings and deviations

• One commit per phase, tests and implementation together, per the dispatch brief, instead of the plan's separate test: and feat: commits.
• No subagents for implementation, per the brief, even though sdd-execute says to use them. I implemented each phase directly with TDD (red, then green). Only the Mode B review ran as an agent.
• P2 (the picker's CSS): the stacked Form with no new component. Two existing rules changed after the 360px check failed:
  • .c-scanner__sitting .c-section__title now wraps, like .c-panel's title already does.
  • .c-field select gets min-width:0; max-width:100%, so a long option can't widen it past its form. This is app-wide: it also covers the lot form's location select. Form.md says so.
• Status line: when clearing the place deletes the sitting, the status line is emptied, as the plan says (no message).
• Measurement mode drops an empty sitting the same way the scanner does (from the review).
• Commit trailers: 31a9a0a and e4bedff say Co-Authored-By: Claude Sonnet 5.5 by mistake. This session ran on Opus 5.5, and every later commit says so. Pushed commits were not rewritten.

Tests

• Whole suite at 7a6256a: 2467 examples, 0 failures, 1 pending (the art agreement example, which needs the spike's cache).
• After the review fixes: 2470 examples (a dry run counts them), run in full by the pre-push bin/ci at 7aa45a1; the scanner model, request and system specs re-run after the fixes: 152 examples, 0 failures.
• New and extended: the migration spec (5 examples), spec/models/scanner/sitting_spec.rb (+16), spec/requests/scanner/sittings_spec.rb (+22), sitting_entries_spec.rb (+5), measurements_spec.rb (+1), apply_spec.rb (2 examples extended), spec/system/scanner_sitting_spec.rb (+5).
• Local bin/ci: passed in full as the pre-push hook at 7aa45a1 (setup, migration guard, RuboCop, Brakeman, bundler-audit, importmap audit, RSpec). One earlier pre-push run failed Upgrade::Harness removes its temporary directory, because another worktree's suite was running at the same time (Flaky: Upgrade::Harness "removes its temporary directory" races other suites through the shared tmpdir #178). It passed on the retry.

Implementation review

SPEC-ALIGNED (sdd-review Mode B, read-only, Opus). The coverage matrix and how each finding was handled are in verification.md.

• Major: verification.md was missing. It has been written.
• Fixed, tests first:
  • The scanner checked whether a sitting was empty and deleted it in two separate steps, so an add from another tab in between could lose its entry. drop_if_pointless! now reloads, checks and deletes in one transaction.
  • Measurement mode now drops empty sittings too.
  • A guard proves another account's locations never appear in the select.
  • Form.md documents the select's width.
• Kept:
  • Focus after "Set" drops to the page, as it does after spec 009's Undo.
  • The status line stays empty when clearing deletes the sitting, because the plan says no message there.
  • place! writes the row twice (insert, then update) when it opens a sitting. This is harmless.

Screenshots

Headless Firefox against this worktree's dev server. Its database was empty, so a scratch script seeded it: one collector, three printings, two locations and an applied refresh run. Tiles show placeholders, not card art.

The add uses a picked photo: the specs' synthetic card, because there is no camera headless. The 390px shots come from a 390px iframe on /collection, because the scanner sends frame-src 'none'. Headless Firefox reports a dark colour scheme, so the walkthrough is dark.

Walkthrough: choose Blue binder, pick a photo, add the Foil copy, and the lot shows Blue binder in the collection.

390px, light	390px, dark

Desktop, light	Desktop, dark

Check by hand

• On a phone with a real camera, choose a place, scan a few cards, and check that the camera keeps running across "Set".
• Remove a location that holds no cards while a sitting names it, then scan a card. The notice should name no place.
• The panel's spacing: the stacked picker sits between the heading and the list.

Closes #56

🤖 Generated with Claude Code

[plainprogrammer]

Follow-ups filed by the coordinator: #182 (keep focus and announce after the sitting panel redraws), #178 (harness tmpdir race). For the maintainer: on a real phone, check the camera keeps running across Set. Note the app-wide CSS change: .c-field select gains min-width:0; max-width:100% so a long location name can't widen a form.