import Foundation /// Reads CrossModel settings from environment variables.public enum CrossModelSettingsReader {    /// Environment variable key for the CrossModel API token.    public static let envKey = "CROSSMODEL_API_KEY"    /// Environment variable key for an optional API base URL override.    public static let urlEnvKey = "CROSSMODEL_API_URL"     /// Returns the API token from environment if present and non-empty.    public static func apiToken(environment: [String: String] = ProcessInfo.processInfo.environment) -> String? {        self.cleaned(environment[self.envKey])    }     /// Returns the API base URL, defaulting to the production endpoint.    public static func apiURL(environment: [String: String] = ProcessInfo.processInfo.environment) -> URL {        if let override = self.validAPIURL(environment: environment) {            return override        }        return URL(string: "https://api.crossmodel.ai/v1")!    }     public static func validateEndpointOverrides(        environment: [String: String] = ProcessInfo.processInfo.environment) throws    {        guard let raw = self.cleaned(environment[self.urlEnvKey]) else { return }        // Loopback HTTP is allowed so the provider can be exercised end-to-end        // against a locally running gateway during development.        guard ProviderEndpointOverrideValidator().validatedURLAllowingLoopbackHTTP(raw) == nil else { return }        throw CrossModelSettingsError.invalidEndpointOverride(self.urlEnvKey)    }     static func cleaned(_ raw: String?) -> String? {        guard var value = raw?.trimmingCharacters(in: .whitespacesAndNewlines), !value.isEmpty else {            return nil        }         if (value.hasPrefix("\"") && value.hasSuffix("\"")) ||            (value.hasPrefix("'") && value.hasSuffix("'"))        {            value = String(value.dropFirst().dropLast())        }         value = value.trimmingCharacters(in: .whitespacesAndNewlines)        return value.isEmpty ? nil : value    }     private static func validAPIURL(environment: [String: String]) -> URL? {        guard let raw = self.cleaned(environment[self.urlEnvKey]) else { return nil }        return ProviderEndpointOverrideValidator().validatedURLAllowingLoopbackHTTP(raw)    }}