fix(cli): satisfy ruff encoding requirement in send_cmd

Specify utf-8 when reading message bodies from --file paths so the full-repo ruff enforcement check passes in CI.

hermes_cli/send_cmd.py

@@ -58,7 +58,7 @@ def _read_message_body(
         if file_path == "-":
             return sys.stdin.read()
         try:
-            return Path(file_path).read_text()
+            return Path(file_path).read_text(encoding="utf-8")
         except OSError as exc:
             print(f"hermes send: cannot read {file_path}: {exc}", file=sys.stderr)
             sys.exit(_USAGE_EXIT)