Refactor Filter Engine: Integrate Payload, ClauseFactory & Dissector for cleaner filter execution

[kettasoft]

Summary

This PR refactors and enhances the core filter engine to make filter expression handling more modular, consistent, and configurable.

Key Changes

• Refactor:
  • Updated Clause constructor to accept a Payload instance, simplifying instantiation and improving clarity.
  • Simplified clause creation by using ClauseFactory directly.
  • Improved test coverage and method mapping in InvokableEngineTest.
• Feature:
  • Introduced allowed SQL operators configuration for filter expressions in the InvokableEngine.
  • Added getter and setter methods for field and operator in the Payload class.
  • Integrated Dissector and ClauseFactory into filter execution for cleaner payload handling.
  • Automatically sets allowed fields from filters in the Invokable Engine.

Why

These changes aim to:

• Improve code readability and reduce coupling between components.
• Allow developers to define custom operator/field configurations more easily.
• Prepare the engine for future CLI and runtime configuration features.
• Strengthen consistency across filters and tests.

Impact

• No breaking changes expected for users of the public API.
• Internal refactors may affect advanced users relying on internal classes (Clause, Payload, InvokableEngine).
• All tests updated and passing.