v0.9.18 - Humble CDN allowlist fix
Live-dogfood fix: Humble downloads refused their own CDN.
Fixed
- Humble Bundle downloads failed with "download URL is outside the provider
allowlist: cdn.humble.com": live Humble serves signed URLs from
cdn.humble.com as well as the dl.humble.com the research fixtures had
observed. The source-download allowlist now trusts the two Humble-operated
apex domains (dot-boundary subdomain matching, HTTPS-only and md5
verification unchanged). (FRG-SRC-006)