fix: report an invalid --port with a short message instead of listing every choice

src/aegis_gitea_mcp/cli.py

@@ -17,6 +17,17 @@ from aegis_gitea_mcp.config import Settings, get_settings, reset_settings
 from aegis_gitea_mcp.logging_utils import configure_logging
 
 
+def _port(value: str) -> int:
+    """Parse ``--port`` (argparse ``type``): an integer from 1 to 65535."""
+    try:
+        port = int(value)
+    except ValueError:
+        raise argparse.ArgumentTypeError("must be an integer from 1 to 65535") from None
+    if not 1 <= port <= 65535:
+        raise argparse.ArgumentTypeError("must be between 1 and 65535")
+    return port
+
+
 def build_parser() -> argparse.ArgumentParser:
     """Build the argument parser."""
     parser = argparse.ArgumentParser(
@@ -35,9 +46,8 @@ def build_parser() -> argparse.ArgumentParser:
     serve.add_argument("--host", default=None, help="HTTP bind address (default: MCP_HOST)")
     serve.add_argument(
         "--port",
-        type=int,
+        type=_port,
         default=None,
-        choices=range(1, 65536),
         metavar="PORT",
         help="HTTP port (default: MCP_PORT)",
     )