Introducing Lead: TIN-compatible full-text search for CI

Introduces Lead, a PostgreSQL full-text search extension designed for CI/development environments. Lead replicates the feature set of TIN (tokenizing, ACID compliance, BM25 scoring, highlighting) but intentionally sacrifices performance by using full table scans. This enables developers to build and test applications that utilize full-text search without the performance demands of TIN in production, offering a cost-effective and functional alternative for non-production use cases.