W-886: Digit quick-pick for the typed-query list - #249

Summary

While the shortcode list is up (:smil), pressing a digit inserts that row, the same way 1–8 already works on the Quick Access pill. Each pickable row shows its digit at the trailing edge, like a menu's key equivalents, and the footer reads ↑↓ ↵ 1–6 insert (1–N when fewer rows match).

Digits cover the rows the list draws without scrolling. That's 6 today (PickerLayout.maxVisibleRows), not the 9 the issue suggests, so a digit never inserts a row you can't see. The state machine allows up to 9, so raising maxVisibleRows extends it.

The collision guard is the one proposed in the issue: a digit picks only when appending it would leave the query with no matches. So :smil + 2 picks the second row, while :clock1 (🕐), :100: (💯) and :+1: still type normally. 0 never picks. A sticky session (Shift+Return) keeps typing digits into its search, and the trailing "Browse all emojis…" row is never a target.

• KeyMonitor/TriggerStateMachine.swift: new .pickListIndex(_:query:scope:) action. A digit picks when listQuickPickCount (the rows the Engine says are on screen) covers it and the Engine-supplied queryHasMatches probe reports that the extended query matches nothing. Any query edit, sticky/browser entry, new capture or reset() disarms the count until the next refresh, so a digit never picks from a stale list. Mid-close (::star:) digits type through. The pill path (emptyPickerActive / .pickIndex) is untouched.
• App/Engine.swift: arms the count from the visible rows it puts in the list, and only during a live capture. The probe is a FuzzyMatcher.search(limit: 1) that runs only when a digit arrives while the list is armed. .pickListIndex goes through the same insert(.fromPicker) path as Return, so the erased span (:query, ::query, or a custom open) matches Return exactly. A digit is never consumed without a row to insert. The probe runs inside stateMachine.handle, so it reads a mirrored copy of the trigger config instead of stateMachine.config, which would be an overlapping access and trap Swift's runtime exclusivity check.
• Picker/PickerView.swift, PickerViewModel.swift, HintsFooter.swift: row badges and the footer hint. KeyHint gains a multi-key form so ↵ and 1–9 share the "insert" label. To fit the 280 pt panel, the arrows drop their "select" label while digits are live; sticky sessions keep the old footer. No new strings.
• Tests/MojitoTests/TriggerStateMachineTests.swift: ListQuickPickTests (13 tests). They cover picking, the collision guard (and what the probe receives), 0, out-of-range digits, unarmed and probe-less states, disarm on edit, :: scope delete length, sticky sessions, the unchanged pill pick, and reset().

Offscreen renders of PickerView (no panel glass):

Light	Dark

Test plan

• Full MojitoTests suite passes locally: 336 tests, built against the macOS 26.5 SDK with the Swift 6.4 command-line tools through a SwiftPM wrapper, because the machine I built this on has no Xcode. The one exception, DebugReportTests.forbiddenStringsNeverAppear, fails the same way on main under that wrapper, since the report sees the runner's non-bundle path.
• scripts/check_localizations.py and scripts/check_telemetry.py pass.
• scripts/run-tests.sh / CI on Xcode.
• In Mojito Dev: :smil then 2 inserts the second row and erases :smil; :clock1 keeps typing; ::star then 1 inserts a symbol and erases ::star; after Shift+Return, digits search in the sticky session; :? then 3 still picks from the pill.

Fixes #204 · Refs W-886