Fix A: `fxhnt fetch --futures` with no DATABENTO_API_KEY now exits 1
with a clear message instead of surfacing a RuntimeError traceback;
guard runs before any network call so crypto still proceeds normally.
Fix B: `fetch_crypto_pit` writes `funding` as a per-day array aligned
to `kd` (same length as `day`/`close`), dropping the separate
`funding_day` key that was unaligned with the price axis.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
