Quick Lookup UX

Two of the README's three journeys end at one answer: I finished X, where do I go next? Quick Lookup is where that answer is delivered, and it currently renders — for every case where the app does not know. Those cases are not all the same, and a dash tells the user nothing about which one they hit.

This skill owns the behaviour contract. The component itself is governed by universal-component; it exists once, in src/components/QuickLookup.tsx, and MappingSection renders it on the series screen. Extend that copy — never fork a second one.

The answer states

episodeToChapters and chapterToEpisodes both return [number, number] | null, and null collapses five distinct situations. Distinguish them:

Situation	How to detect	What to say
Answered	tuple returned	chapters 41-80. Include the season when known, as the manga copy already does.
Input beyond the mapped range	value exceeds the last arc's end	"The catalog maps through episode N." Not a dash.
Input inside a gap between arcs	value falls between two arcs	"Not covered by a mapped arc" — this is filler or a skipped stretch, and saying so is the useful answer.
Chapter is in an unadapted arc	arc matched, episodes is undefined	"Not animated yet." This is a good answer for a manga reader and must not look like a failure.
No mapping exists at all	findMapping missed and buildSyntheticMapping returned null	Explain that the series is unmapped, and link to contributing a mapping.

Auto-estimated mappings

When findMapping misses, buildSyntheticMapping distributes episodes evenly across chapters and sets sourceNotes to a warning that real arc pacing is rarely uniform. That warning must be visible wherever the estimate is used, not only on the series header. An estimated Quick Lookup answer is a guess and has to read like one:

≈ chapters 41-80  (estimated — this series has no curated arc mapping)

Use COLOR.notice for estimated answers, never COLOR.textPrimary. A confident-looking wrong answer is worse than no answer, because the user buys the wrong volume.

Ongoing series

For a manga still publishing, the last arc ends at the last published chapter, not at the end of the story. When a lookup lands in the final arc, say so: "you are current through chapter N". Do not imply the series ends there.

Consistency rules

• One vocabulary. Episodes are cumulative across seasons everywhere in the UI, matching the catalog. Never show a per-season episode number in one place and a cumulative one in another.
• Ranges render identically in Quick Lookup, the rail, arc detail, and the progress banner. Route them through one formatter in src/data/format.ts.
• Volume, not just chapter. An anime viewer's real question is which book to buy. Where MangaDex volume data is loaded, pair the chapter answer with its volume.

Common mistakes

Mistake	Consequence
Rendering — for every null	Five different situations look like one failure.
Styling an estimated answer like a curated one	The user buys the wrong volume and trusts the app less.
Adding a state to one copy of QuickLookup	The anime and manga copies drift further. Unify first.
Treating "not animated yet" as an error	For a manga reader that is the answer they wanted.
Formatting a range inline	Four call sites drift. Use src/data/format.ts.