Move db off from neon to self hosting

[peetzweg]

Reached free tier of neon. time to move to self hosting to cut costs.

[peetzweg]

Related: PR #120 adds indexes + bounds the hottest query (the recent-lookups strip currently aggregates the whole lookups table on every poll — likely a real contributor to the Neon compute burn). The migration is unapplied; the cutover here is a natural moment to run it (drizzle-kit migrate against the new DB picks up 0006 automatically).

[peetzweg]

Done — prod has been running on self-hosted Postgres 18 (Coolify) since 2026-07-16. Driver swap in #128, dev-database + preview isolation via #130's tooling, backups automated offsite. Detailed runbook lives in the devops repo (peetzweg/devops#4).