fix(nginx): correct real_ip_header typo X-Forward-For → X-Forwarded-For (#8935)

X-Forward-For is not a real HTTP header — the standard is X-Forwarded-For.
With the typo, Nginx never replaces $remote_addr with the actual client IP,
so rate limiting and IP logging see the proxy IP instead of the real client.
Affects all three nginx configs (web, admin, space).