Fix database connection exhaustion in tests by setting max_conns=1
when creating pgxpool via pgxpool.ParseConfig().
- Update setupTestServer() in test_helpers.go
- Update setupSyncTestDB() in sync_integration_test.go
This reduces per-test connection usage from 4 to 1, keeping total
connections well under PostgreSQL's default max_connections=100.
78 tests × 1 connection = 78 connections (down from 312 potential)
Fixes test failures: "FATAL: sorry, too many clients already"
See PROJECT_GUIDELINES.md Testing section for details.
john-okeefe
891209b4bd