Add config package with build-tag-switched dev/prod environments,
structured logging via zerolog, Taskfile for dev workflow, golangci-lint
config, testutil package, and improved DB setup with proper SQLite
pragmas and cleanup. Rename sqlc output package from gen to repository.
Switch to allowlist .gitignore, Alpine+UPX+scratch Dockerfile, and
CI pipeline with test/lint gates before deploy.
Embed full assets directory and serve with via's StaticFS instead of a
custom HTTP handler. Move SQLite DB to data/c4.db for clean volume
mounting. Add multi-stage Dockerfile, docker-compose.yml, and
.dockerignore.