Function cacheKeyToFilename

src/api/providers/fetchers/modelCache.ts:153–160

* Convert a cache key to a filesystem-safe filename component. * Hashes the full key to guarantee uniqueness while preserving a readable * provider prefix at the start of the filename.

(cacheKey: string)

 * provider prefix at the start of the filename.
 */
function cacheKeyToFilename(cacheKey: string): string {
	const prefix = cacheKey.split(":")[0] // provider name -- always filesystem-safe
	// The compound cache key embeds the API-key discriminator, so it is treated as
	// password-tainted by static analysis; deriveCacheDigest keeps the filename derivation
	// off the weak-hash sink while still producing a collision-free, irreversible component.
	const hash = deriveCacheDigest(cacheKey, FILENAME_DIGEST_BYTES)
	return `${prefix}_${hash}`
}

async function writeModels(cacheKey: string, data: ModelRecord) {
	const filename = `${cacheKeyToFilename(cacheKey)}_models.json`