Feat/schema diff

[heaven00]

Adds tool to query table schema diff using pipeline and table name

• Compare with previous by default
• Add capability to look up schema by version hash when another is provided
• Handle edge case for when there is no schema change
• Manual testing using continue.dev tooling

[heaven00]

Tested by using it in the continue chat querying about the pipelines, tables in a particular pipeline and then if anything has changed in the table?

Yes, the users table schema has changed.

Schema Change Summary:

• Added column: age (data_type: 'bigint', nullable: True)
• The age column was added to the users table schema

This is a schema evolution where a new column was introduced to the existing users table. The change shows that the table now includes an 'age' field that can store integer values and may be null.

I am still not 100% sure about how to do the time based query to make the llm fetch version hash for a particular time period