lith/Caddyfile: restore Caddy-side CORS on ipfs gateway
Turns out Kubo doesn't emit Access-Control-Allow-Origin by default; only the
other access-control-* headers. Previous pass-through commit left the gateway
with zero CORS header. Re-add it at the Caddy layer.
The original "*, *" dupe was Cloudflare (or a WAF Transform Rule) stacking on
top of Caddy, not Kubo. If the dupe returns, fix it at Cloudflare.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>