Verify the AssemblyAI webhook's shared-secret header. Vendor-specific by design: the env var,
the header and the error are all AssemblyAI's — only the constant-time compare is shared.
Throws
AssemblyAIWebhookAuthError on misconfiguration ("missing-secret")
or on a missing/wrong header ("invalid-secret"). The caller decides how to
surface these — typically 4xx for misconfig, 401 for invalid.
Verify the AssemblyAI webhook's shared-secret header. Vendor-specific by design: the env var, the header and the error are all AssemblyAI's — only the constant-time compare is shared. Throws AssemblyAIWebhookAuthError on misconfiguration ("missing-secret") or on a missing/wrong header ("invalid-secret"). The caller decides how to surface these — typically 4xx for misconfig, 401 for invalid.