fix(cli): resolve SQL directory at runtime for bundled CLI

The sqlDir() function was using __dirname which gets baked in at build time by bundlers (bun/esbuild), causing prepare-db --print-sql to fail when run from npm-installed package.

Changes:

• Use import.meta.url with fileURLToPath for runtime path resolution

• Copy SQL files to dist/sql during build

• Add CI smoke test to verify prepare-db --print-sql works

  Related issue: https://gitlab.com/postgres-ai/platform/-/issues/346