Adds two new webhook trigger signing modes for external provider
compatibility:
- github_hmac: accepts X-Hub-Signature-256 header with
HMAC-SHA256(secret, rawBody), no timestamp prefix. Compatible with
GitHub, Sentry, and services following the same standard.
- none: no authentication; the 24-char hex publicId in the URL acts
as the shared secret. For services that cannot add auth headers.
The replay window UI field is hidden when these modes are selected
since neither uses timestamp-based replay protection.
Closes#1892
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
cd19834fab