/**
 * Default Chrome profile discovery (plan Phase 2 wiring).
 *
 * Locates the user's real Chrome "Default" profile directory per OS so the
 * default headless launch path can warm up synthetic sessions from an isolated
 * copy of it (see profile-warmup.ts + profile-posture.ts). Pure path logic with
 * an injectable existence check, so it is unit-testable without touching the
 * real filesystem.
 */
export interface DiscoveryEnv {
    platform: NodeJS.Platform;
    home: string;
    /** Injectable for tests; defaults to fs.existsSync at call sites. */
    exists: (p: string) => boolean;
    /** Windows LOCALAPPDATA override (tests / non-default installs). */
    localAppData?: string;
    /** Linux Chrome-specific default user-data override. */
    chromeUserDataDir?: string;
    /** Linux Chrome config-home override (takes precedence over XDG_CONFIG_HOME). */
    chromeConfigHome?: string;
    /** Linux XDG config-home override. */
    xdgConfigHome?: string;
}
/** Candidate Chrome user-data roots for the platform (most common first). */
export declare function chromeUserDataRoots(env: DiscoveryEnv): string[];
export interface DiscoveredProfile {
    userDataDir: string;
    profileDirectory: string;
    profileDir: string;
}
/**
 * Discover the default Chrome profile, or null when none is present.
 * Only returns a profile whose directory actually exists.
 */
export declare function discoverDefaultChromeProfile(env: DiscoveryEnv, profileDirectory?: string): DiscoveredProfile | null;
/** Convenience wrapper using the live OS environment + fs. */
export declare function defaultDiscoveryEnv(exists: (p: string) => boolean): DiscoveryEnv;