[DevEx]: Convert the game store to TypeScript #1427

Part of #1399. The last and largest of six store issues. Do this after #1422, #1423, #1424, #1425, #1426 — the conventions and the shared interfaces should be settled before touching this file.

Summary

Convert src/stores/game.js to TypeScript. 935 lines, 36 ref declarations, 54 functions — the largest and highest-value file on the frontend, and the source of most of the unknown types that surface as errors in components.

Why this is the one that matters

The untyped-prop errors across the component tree mostly originate here. spectatingUsers is unknown inside SpectatorListMenu.vue because it is ref([]) in this store. Typing the prop fixes the symptom at one component; typing the store fixes it at the source for every consumer.

The state is declared almost entirely as empty or null literals:

const id = ref(null);
const chat = ref([]);
const deck = ref([]);
const log = ref([]);
const players = ref([]);
const spectatingUsers = ref([]);
const scrap = ref([]);
const twos = ref([]);
const oneOff = ref(null);
...

so the checker learns nothing about any of them.

The real work is the payload boundary

updateGame(newGame) takes an untyped parameter and fans it out across ~20 assignments:

spectatingUsers.value = newGame.spectatingUsers ?? spectatingUsers.value;
players.value = newGame.players?.map((player) => setPlayers(player)) ?? players.value;
oneOff.value = createGameCard(newGame.oneOff) ?? null;
status.value = newGame.status ?? GameStatus.ARCHIVED;

Every field access on newGame is any. Declaring that payload shape is most of this issue, and it is where the value is: a renamed or mistyped field is invisible today and would be caught immediately once declared. That is structurally the bug that blanked the game log for months in #1386.

docs/game-state-api.md describes the socket payload and the GameState shape, and was refreshed in #1398, so its enum lists are current. It is the right starting reference — but verify against api/helpers/game-states/create-socket-events.js, which is what actually constructs the payload.

Suggested sequencing

Reasonable to split across several PRs:

1. The card/player shapes (createGameCard, setPlayers) — small, shared, and depended on by everything else
2. The GameUpdate payload interface + updateGame
3. The remaining state refs and the computeds
4. The socket request functions

Coordination — this file is contended

Three open PRs touch src/stores/game.js: #1384 (fours rework), #1383 (socket helper refactor), #1378 (nines rework). A 935-line file conversion will conflict with all of them. Land those first, or agree a window. This is the main reason to sequence this issue last.

Acceptance

• src/stores/game.js becomes src/stores/game.ts
• The socket payload consumed by updateGame has a declared interface
• No any left on state declarations; ref([]) / ref(null) replaced with explicit type parameters
• All call sites still type-check
• npm run build succeeds; full Cypress suite passes — this store backs the entire in-game experience, so the e2e suite is the real safety net

Why TS and not JSDoc

Measured: this store reports 0 errors under checkJs across 935 lines — silence, not correctness. Four realistic bugs injected into updateGame():

noImplicitAny is not a cheap middle ground — it takes this file from 0 to 128 errors, all TS7006 "annotate this", while catching none of the missed bugs.

No build change required

Vite transpiles .ts today via esbuild, with no new dependency — verified, exit 0. esbuild only strips types, so checking comes from vue-tsc in CI (#1400, #1409).