function getTenantCachePrefix getTenantCachePrefix(ctx: { state: Map<string, unknown>; }): string | undefined Exported accessor that reads the cache-prefix stamped into ctx.state by the middleware. Consumers never hardcode the state key string. Parameters ctx: { state: Map<string, unknown>; } Must expose a state: Map<string, unknown> (satisfied by IRequestContext). Return Type string | undefined The prefixed cache key, or undefined when not configured.