Document that `rtk curl` (and siblings `cat`, `read`, `json`, etc.)
emits the compressed/schema representation even when stdout is piped,
silently breaking any downstream parser (jq, python json.load, awk).
Proposes an isatty(stdout) check to passthrough raw bytes when not
a TTY, matching the Unix convention used by ls/grep/diff.
Co-Authored-By: Claude <noreply@anthropic.com>
