Getting connected

The course on-ramp: who you are, what Brew is, and what we'll build (an intro map unit), then the first technical layer — client-server, the local sandbox (postgres:18 + Adminer), psql as a working tool, connecting from Go via pgxpool, and typed queries via sqlc. After this module you have a working pipeline — "SQL by hand → sqlc generate → typed pgx code" — that every other topic builds on.