Seed CI test fixtures

Problem: every CI run needs the same realistic database, fast, with no network access.

Solution:

pip install dbsprout
dbsprout init --file schema.sql
dbsprout generate --seed 42 --rows 200
dbsprout validate --format json --output validate.json

Commit dbsprout.toml and the .dbsprout/ snapshot so every machine regenerates byte-identical fixtures. Example GitHub Actions step:

- run: |
    pip install dbsprout
    dbsprout generate --seed 42 --rows 200
    dbsprout validate --format json --output validate.json

Why it works: the default heuristic engine needs no model or network and runs at 100K+ rows/sec. A fixed --seed makes output identical across runs and machines; validate --format json gives CI a machine-readable pass/ fail.