Wrap Record types in Partial for propertyNames

[nolannbiron]

Problem

propertyNames in JSON Schema only constrains which keys are allowed on an object, it does not make them required. However, the generated TypeScript output uses Record<K, V>, which requires all keys to be present.

For example, given a schema with propertyNames referencing an enum [en, fr, de, es], the output was:

export type LocalizedString = Record<TranslationLanguage, string>;

This incorrectly requires all enum values as keys.

Solution

When propertyNames is present, wrap the generated Record<K, V> with Partial<> in the primitive schema parser. Without propertyNames, plain additionalProperties with string keys continues to generate Record<string, V> as before.

The fix is a single conditional in src/schema-parser/base-schema-parsers/primitive.ts: if a propertyNamesSchema exists, the output becomes Partial<Record<K, V>> via the existing TypeWithGeneric construct.

Verification

Updated the propertyNames test snapshot to expect Partial<Record<KekEnum, number>> in both top-level type aliases and nested interface fields.

Fixes #1642

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Latest commit: 9609f0d

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swagger-typescript-api	Minor

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[js2me]

LGTM! I think it's ok :)