fix: Redis cache, BullMQ webhook queue, pg_trgm migration, Prisma pool tuning (#775 #776 #777 #778) - #893

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@v4, actions/setup-node@v4. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/