fix(api): improve SQL query result type handling and formatting

[jdhoffa]

This PR fixes issues with SQL data type handling in the query endpoint and standardizes SQL query output format.

The changes address two key issues:

1. Fix the SQL query result handling in the API to properly handle various PostgreSQL data types, preventing null values in the response
2. Ensure consistent SQL query formatting in the LLM processor by adding explicit formatting instructions

The improved type handling includes:

• Explicit handling for common data types (integers, floats, strings, booleans)
• Multiple fallback mechanisms for custom or complex types
• Better type information in error cases

Resolves the issue where SQL query results would return null values for certain data types.

[Copilot]

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.