chore: ignore pgsql-test output directory in git

Remove test-generated CSV files from git tracking and add output directory
to .gitignore. These files are generated during test runs and should not be
committed.

- Remove packages/pgsql-test/output/users.csv
- Remove packages/pgsql-test/output/posts.csv
- Add packages/pgsql-test/output/ to .gitignore

Author: sdqede

.gitignore

@@ -4,4 +4,5 @@
 **/pnpm-debug.log
 lerna-debug.log
 .vscode
-ignore
+ignore
+packages/pgsql-test/output/