Adds @drakkar.software/starfish-webhook: inbound-webhook ingestion with pluggable
auth (HMAC-SHA256 secret or custom verifier), sealed-write E2EE for keyless writers,
and generateSignerKeypair() in starfish-protocol. Lockstep bump of all 29 packages
from 3.0.0-alpha.24 to 3.0.0-alpha.25.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>