feat: add CLI for binary management (Python + JavaScript)

Adds install, info, update, and clear-cache subcommands with visible
download progress. Python: `python -m cloakbrowser install`. JavaScript:
`npx cloakbrowser install`. Useful for Dockerfiles where silent
first-use downloads are hard to debug. Closes #43.

cloakbrowser/__main__.py

@@ -0,0 +1,111 @@
+"""CLI for cloakbrowser — download and manage the stealth Chromium binary.
+
+Usage:
+    python -m cloakbrowser install      # Download binary (with progress)
+    python -m cloakbrowser info         # Show binary version, path, platform
+    python -m cloakbrowser update       # Check for and download newer binary
+    python -m cloakbrowser clear-cache  # Remove cached binaries
+"""
+
+from __future__ import annotations
+
+import argparse
+import logging
+import sys
+
+
+def _setup_logging() -> None:
+    """Route cloakbrowser logger to stderr with clean output."""
+    logging.basicConfig(
+        level=logging.INFO,
+        format="%(message)s",
+        stream=sys.stderr,
+        force=True,
+    )
+    # Suppress noisy HTTP request logs from httpx
+    logging.getLogger("httpx").setLevel(logging.WARNING)
+
+
+def cmd_install(args: argparse.Namespace) -> None:
+    from .download import ensure_binary
+
+    path = ensure_binary()
+    print(path)
+
+
+def cmd_info(args: argparse.Namespace) -> None:
+    from .config import get_local_binary_override
+    from .download import binary_info
+
+    info = binary_info()
+    override = get_local_binary_override()
+
+    print(f"Version:   {info['version']}")
+    print(f"Platform:  {info['platform']}")
+    print(f"Binary:    {info['binary_path']}")
+    print(f"Installed: {info['installed']}")
+    print(f"Cache:     {info['cache_dir']}")
+    if override:
+        print(f"Override:  {override} (CLOAKBROWSER_BINARY_PATH)")
+
+
+def cmd_update(args: argparse.Namespace) -> None:
+    from .download import check_for_update
+
+    logger = logging.getLogger("cloakbrowser")
+    logger.info("Checking for updates...")
+    new_version = check_for_update()
+    if new_version:
+        print(f"Updated to Chromium {new_version}")
+    else:
+        print("Already up to date.")
+
+
+def cmd_clear_cache(args: argparse.Namespace) -> None:
+    from .config import get_cache_dir
+    from .download import clear_cache
+
+    if not get_cache_dir().exists():
+        print("No cache to clear.")
+        return
+    clear_cache()
+    print("Cache cleared.")
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        prog="cloakbrowser",
+        description="Manage the CloakBrowser stealth Chromium binary.",
+    )
+    sub = parser.add_subparsers(dest="command")
+
+    sub.add_parser("install", help="Download the Chromium binary")
+    sub.add_parser("info", help="Show binary version, path, and platform")
+    sub.add_parser("update", help="Check for and download a newer binary")
+    sub.add_parser("clear-cache", help="Remove all cached binaries")
+
+    args = parser.parse_args()
+    if not args.command:
+        parser.print_help()
+        sys.exit(2)
+
+    _setup_logging()
+
+    commands = {
+        "install": cmd_install,
+        "info": cmd_info,
+        "update": cmd_update,
+        "clear-cache": cmd_clear_cache,
+    }
+
+    try:
+        commands[args.command](args)
+    except KeyboardInterrupt:
+        sys.exit(130)
+    except Exception as e:
+        print(f"Error: {e}", file=sys.stderr)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()