Build a real database seeder

The current db:seed and db:wipe scripts drive the live HTTP API with an admin cookie and real Spotify calls, so they need a running server, network access and an admin password to produce test data. That makes deterministic e2e tests impossible.

• Write a seeder that inserts fixture data directly through Drizzle: a known set of artists, albums, tracks, genres, links and scores
• Deterministic output, same input every run, no network
• Wire it up as db:seed; rename the old API-driven scripts to smoke:* or delete them
• The fixture set should cover what the e2e flow needs: reviewed albums, an unreviewed searchable album, bookmarks, multi-artist albums