feat: expose CURRENCY field settings (format/decimals) in shared types (#21090)

## What

Add a `CURRENCY` entry to `FieldMetadataSettingsMapping` (a
`FieldMetadataCurrencySettings` type of `{ format?: 'short' | 'full';
decimals?: number }`) so `FieldMetadataSettings<CURRENCY>` resolves to
the real settings shape instead of `null`.

## Why

The currency **format** (Short/Full) and **decimals** selectors already
ship in the field settings UI and persist through the generic `settings`
jsonb column — they render via
[`CurrencyDisplay.tsx`](https://github.com/twentyhq/twenty/blob/main/packages/twenty-front/src/modules/ui/field/display/components/CurrencyDisplay.tsx)
reading `settings.format` / `settings.decimals` (added in #12542 and
#16439).

But `twenty-shared` never got a `CURRENCY` entry in the settings
mapping, so `FieldMetadataSettings<CURRENCY>` is `null`. The SDK's
`defineField` derives its types from this mapping, so an app author
cannot set these from code — `universalSettings: { format: 'full',
decimals: 2 }` on a CURRENCY field is a type error, even though the
server stores and the frontend honours it. This aligns the type layer
with the already-shipped runtime behaviour.

## Changes

- `twenty-shared`: add `FieldMetadataCurrencySettings` +
`FieldCurrencyFormat`, wire the `CURRENCY` mapping entry, export
`FieldCurrencyFormat`.
- `twenty-server`: move `CurrencyFieldMetadata` from the
`NotDefinedSettings` assertions to a defined-settings assertion in the
field-metadata entity type test.

No runtime change — the server already accepts and stores these settings
via the generic jsonb column; this only makes them visible to the type
system and the SDK.

## Test plan

- [ ] `npx nx typecheck twenty-shared` / `twenty-server` pass
- [ ] In an app, `defineField({ type: FieldType.CURRENCY,
universalSettings: { format: 'full', decimals: 2 }, ... })` type-checks
and deploys
- [ ] Field renders with 2 decimals in full format, matching the
equivalent UI configuration

> Follow-up (not in this PR): the frontend keeps its own local
`fieldMetadataCurrencyFormat` / `FieldCurrencyFormat`; it could import
the shared `FieldCurrencyFormat` to de-duplicate.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

packages/twenty-server/src/engine/metadata-modules/field-metadata/types/__tests__/field-metadata-entity.test-type.ts

@@ -114,7 +114,6 @@ type NotDefinedSettings = {
 
 // oxlint-disable-next-line unused-imports/no-unused-vars
 type SettingsAssertions = [
-  Expect<HasAllProperties<CurrencyFieldMetadata, NotDefinedSettings>>,
   Expect<HasAllProperties<FullNameFieldMetadata, NotDefinedSettings>>,
   Expect<HasAllProperties<RatingFieldMetadata, NotDefinedSettings>>,
   Expect<HasAllProperties<SelectFieldMetadata, NotDefinedSettings>>,
@@ -145,6 +144,16 @@ type SettingsAssertions = [
       }
     >
   >,
+  Expect<
+    HasAllProperties<
+      CurrencyFieldMetadata,
+      {
+        settings: JsonbProperty<
+          FieldMetadataSettingsMapping[FieldMetadataType.CURRENCY]
+        >;
+      }
+    >
+  >,
   Expect<
     HasAllProperties<
       DateFieldMetadata,