forzagreen / n2words / 33686344405

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feat(core)!: stop bare tags from inheriting a country's default currency (#436)

A bare tag names a language; a default currency belongs to a country. `en-US`
defaults to USD because a locale has a country and a country has a currency.
`en` has no country — so inheriting en-US's default meant `n2words/en`'s
toCurrency(42.50) quietly returned dollars to a caller who asked only for
English, across sixteen variants spanning USD, GBP, INR, KES, NGN and ZAR.
Same shape for es -> EUR (against es-MX/MXN and es-US/USD) and fr -> EUR.

Each of the 46 alias files now shadows `toCurrency` and `currencyDefaults`,
using the same mechanism a locale profile uses to override a default:

  toCurrency(42.50)                      // TypeError
  toCurrency(42.50, { currency: 'GBP' }) // 'forty-two pounds and fifty pence'

Region-qualified entry points are untouched — `n2words/en-US` still defaults
to USD, which is the whole point of the distinction. `toCardinal`, `toOrdinal`,
`currencyValues` and `currencyMax` stay reference-identical to the target's.

Three details:

- `currencyDefaults` is derived from the target's rather than hand-listed, so
  an option added to the target later can't silently go missing here.
- The target's own options contract runs first, so a typo'd key reports itself
  (`Unknown option "currencey"`) instead of being masked by the missing-currency
  error. TypeError is right for both — resolve-options.js reserves TypeError for
  shape errors and RangeError for values outside a declared set, and an absent
  required option is a shape error.
- A language that hardcodes one currency has no `currency` option and so
  nothing to strip; its alias stays a plain `export *`. The gate keys off
  exactly that, making the wrapper mandatory the moment such a language gains
  the option.

test/bare-tag-contract.test.js drops toCurrency/currencyDefaults from the
blanket identity list and asserts the new contract instead: the wrapper is a
distinct function, no `cu... (continued)

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