Add PostgreSQL Connection Pooling and Query Optimization

[carlos-israelj]

Description

No connection pooling configured. Each request creates new database connection, causing high latency and connection limit issues at scale.

Current State

Direct Prisma queries without pooling.

Problems

• High latency (connection overhead)
• Connection limit reached at scale
• Slow queries not optimized
• No query performance monitoring

Proposed Solution

Configure PgBouncer for connection pooling and optimize slow queries.

Acceptance Criteria

• PgBouncer configured (transaction mode)
• Connection pool size optimized (min: 5, max: 20)
• Slow query logging enabled (>100ms)
• Database indexes optimized
• N+1 query issues resolved
• Query performance monitoring
• <50ms p95 query latency

ETA

1-2 weeks