feat(prefs): ask which view to open on, and remember the answer

`view` was component state, so a reader who preferred the timeline was put
back on the list by every reload — and which view opened at all had been
decided for them twice over: the PRD said calendar, the app shipped the list.
Neither was the reader's answer.

So the first run asks, and the tabs write to `prefs` from then on. The
question ships pre-answered with the list, because a reader cannot choose
between two layouts they have not seen and that is the one that answers "what
expires next" in a look — and each option is drawn rather than described, for
the same reason. The screen says where to change it afterwards, since the tabs
are small text in a corner.

Adds `view` to the prefs key space. Additive and defaulted, so an existing
reader's stored prefs open exactly where they did before.

Co-Authored-By: Claude Opus 5 (1M context) <[email protected]>

docs/ARCHITECTURE.md

@@ -108,7 +108,7 @@ src/
       Fireworks.tsx     the burst when the last daily lands
       GameFocus.tsx     one game at a time          (F4a)
       Controls.tsx      games, region, export/import(F4, F5, F6)
-      Welcome.tsx       first-run game picker       (F8)
+      Welcome.tsx       first-run games and view    (F8)
       Toast.tsx         undo an ignore
       UpdateNotice      a newer app is installed and waiting  (F14)
       YourOwn.tsx       the reader's own games, in settings   (F13)
@@ -119,7 +119,7 @@ src/
       useMarkSet.ts     ignores (and the superseded completions shape)
       useProgress.ts    status, effort, note, daily override  (F12)
       useDailyLog.ts    which game-days are ticked off
-      usePrefs.ts       region, filters, focus, onboarding flags
+      usePrefs.ts       region, filters, focus, view, onboarding flags
       useCustom.ts      the reader's own games and events     (F13)
       gameMeta.tsx      lane id → name, label, hue; resolves custom lanes too
       sort.ts           deadline order, or what you're partway through

docs/DATA-MODEL.md

@@ -200,7 +200,7 @@ Namespaced, versioned, and small. Nothing here ever goes to the server.
 "gacha-tracker:v1:progress"     // { [eventId]: { status?, effort?, note?, at } }
 "gacha-tracker:v1:daily"        // { [id]: { days: ["2026-08-15", ...], at } }
 "gacha-tracker:v1:ignored"      // { [eventId]: { at } }  — "stop showing me this"
-"gacha-tracker:v1:prefs"        // { region, hiddenGames[], focusGame, sort, detectDaily,
+"gacha-tracker:v1:prefs"        // { region, hiddenGames[], focusGame, sort, view, detectDaily,
                                 //   showCompleted, showIgnored, regionConfirmed, onboarded }
 "gacha-tracker:v1:completions"  // SUPERSEDED — read once to migrate, never written
 ```

docs/FEEDBACK.md

@@ -303,7 +303,7 @@ diagnosis in each item still holds — what changed is whether it has been acted
 | P1a Arknights | **Done.** `arknights-akwiki-events`, via the new `akwiki` parser |
 | P1b `NextUp` → three | **Done** (2026-08-18). One headline and two behind it, off `nextToExpire` |
 | P1b cap the long list | **Not done.** No "show all N" expander |
-| P1b persist `view` | **Not done.** Still `useState` in `App.tsx` |
+| P1b persist `view` | **Done** (2026-08-18). `prefs.view`, and the first run now asks which one to open on (PRD F8) |
 | P1b Calendar → Timeline | **Done.** The tab reads "Timeline" |
 | P1c more games | **Done, four of them.** Infinity Nikki, Persona 5: The Phantom X, Reverse: 1999, Blue Archive — one commit each. Of the games named in the thread, Azur Lane and Umamusume are **declined on conduct** rather than pending, and the declined and cleared-but-unbuilt candidates are recorded in `AGENTS.md` § Scraping conduct so they are not re-litigated |
 | P1c roadmap in the colophon | **Not done** |

docs/PRD.md

@@ -70,8 +70,13 @@ unknown" — it must be visually distinct from an event that ends far in the fut
 **F2 — Ends-soonest list.**
 A flat list of all *currently running* events sorted ascending by end date, with a relative
 countdown ("ends in 2 days", "ends in 4 hours"). Under 24 hours, the row is emphasized. This is the
-view that justifies the app; it should be reachable in one tap from the calendar and is the better
-default on narrow screens.
+view that justifies the app, and it is one tap from the timeline.
+
+**Which view opens is the reader's answer, not ours.** This spec said "calendar (default)" and the
+app shipped opening on the list; both were a decision made on the reader's behalf and then forgotten
+on every reload. So the first run asks (F8) and the answer is stored in `prefs.view`. The list is
+what the question ships pre-answered with — a reader cannot choose between two layouts they have not
+seen, and it is the view that answers "what expires next" in one look.
 
 **F3 — Mark completed.**
 A toggle on every event, in both views. State is written to `localStorage` immediately and
@@ -149,13 +154,19 @@ Four constraints, each protecting something that already exists:
   which is the same argument the code already makes for streaks. This is the *only* copy — there is
   no server to restore from.
 
-**F8 — First-run game picker.**
-Before any events are shown, the reader picks which games they play. A calendar full of games they
+**F8 — First-run setup.**
+Before any events are shown, the reader picks which games they play, and how they want to read
+them. A calendar full of games they
 don't play is worse than an empty one — it buries the thing they came for. Nothing is preselected
 and the button stays disabled until something is chosen; guessing on their behalf and hoping they
 notice is worse than asking. The choice is stored as *hidden* games, the inverse, so a game added
 later appears by default rather than staying invisible forever.
 
+The view question (F2) sits under it, with each option drawn rather than only described — the words
+"list" and "timeline" mean nothing until you have seen this app's version of them. Unlike the games,
+it arrives already answered, and the screen says where to change it afterwards: the tabs are small
+text in a corner, which is the one control a first-time reader will not find on their own.
+
 **F9 — Ignore an event.**
 Distinct from completing one. "Done" keeps an event visible and counted; "not interested" removes it
 from both views entirely. Ignored events stay recoverable: a count and a reveal toggle appear in