i18n-keys

# i18n keys `pnpm lint:i18n-keys` (tools/nx-plugins/enforce-i18n-keys) checks that every key used in `features/`, `domain/` and `shared/` exists in the English catalog of each app consuming the package: Desktop `static/i18n/en/app.json`, Mobile `src/locales/en/common.json`. `.web.*` files are checked against Desktop only, `.native.*` against Mobile only. Other locales are not checked: only edit English. ## Principle: the feature owns its keys A feature resolves its own wording with `useTranslation()`. Apps must not inject keys or labels into features: pass a domain id or variant (`stage`, `status`) and let the feature map it to wording. A key prop coming from `apps/*` is a smell; key props between components of the same package are fine. ## Write keys the check can verify A key is verified when its type is a finite set of literals. A key typed `string` is **unverifiable**: it is counted and the count may never go up (`unverifiable-baseline.json`). Prefer, in this order: 1. **Literal at the call site**: `t("payTab.login.title")`. Greppable, needs no types. 2. **Domain union, key derived in one place**: a new member fails the check until its key exists. ```ts type Stage = "intro" | "login"; declare const stage: Stage; t(`payTab.login.${stage}.title`); // every Stage member is expanded and checked ``` 3. **Internal prop typed as a union of full keys**: last resort, it duplicates key strings in a type. ```ts type Props = { titleKey: "x.intro.title" | "x.login.title" }; ``` What widens a key to `string` and hides it: ```ts const COPY: Record<Id, { titleKey: string }> = { ... }; // annotation widens: use as const satisfies const rows = [{ key: "a" }, { key: "b" }]; // add as const function labelKey(kind: Kind): string { ... } // annotate the literal union ``` Template spans must be unions or literal consts, not `string` or `number`. Template keys are not greppable: the check, not search, protects a "dead" key from deletion. ## When the check fails - **missing in an app**: add the key to that app's English catalog. - **unverifiable count went up**: narrow the type (above), never raise the baseline. - **count went down** (CI fails until the baseline is lowered): run `node tools/nx-plugins/enforce-i18n-keys/validate.js --update-baseline`. - **a union member has no key in an app**: add the key, or remove the member if that app never uses it. `allowMissing` in `unverifiable-baseline.json` lists known gaps for the owning product team to fix; do not add to it without a reason in the PR. - **stale `allowMissing` entry**: the gap is fixed, remove the entry.