v1.0.1 — Improved Error Transparency Across PostgreSQL Components

This release enhances observability and diagnostic precision throughout the PostgreSQL integration layer (PgTypes, PgConnectionLibpq, PgPool, PgTransaction, PgNotificationListener).
Key improvements:

• Unified QueryResult structure now includes detailed error codes (PgErrorCode), SQLSTATE, detail, and hint fields.
• All connection, I/O, and protocol failures now populate QueryResult instead of returning silently.
• PgConnectionLibpq and PgPool now distinguish between transport, server, and logical errors.
• PgNotificationListener logs connection and socket issues with contextual PgErrorCode labels.
• Transactions and connection pool operations now surface meaningful error diagnostics for logging and recovery strategies.

This version focuses on making every failure path explicit and traceable, eliminating silent returns and adding consistent error metadata for higher-level decision logic.