Expand filters available for long-term search in the MCP and API servers

[abrookins]

Summary

This PR enhances the long-term memory search functionality by implementing a more robust filtering system that leverages proper filter objects in both the API and MCP interfaces.

Changes

• Improved API Type Safety: Updated SearchPayload to use filter objects (SessionId, Namespace, etc.) directly as fields instead of primitive types
• Comprehensive Query Support: Added support for complex filtering operations across all filter types:
  • Tag filters (session_id, namespace, topics, entities, user_id)
    • Equal to/not equal to specific values
    • Contains any/all of specified values
  • Numeric filters (created_at, last_accessed)
    • Greater than/less than
    • Greater than or equal to/less than or equal to
    • Equal to/not equal to
    • Between two values
• Simplified API/MCP Integration: Created create_with_primitives method to enable easy construction of filter objects from primitive values
• Enhanced MCP Tool Interface: Expanded MCP tool with comprehensive filtering parameters while maintaining backward compatibility
• Updated Tests: Added test coverage for all new filtering capabilities

Motivation

Previously, the filtering functionality was limited and didn't fully leverage the filter objects defined in filters.py. This update provides a more powerful, type-safe, and flexible filtering mechanism that simplifies complex queries.

[Copilot]

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

[abrookins]

Tools CAN use BaseModels for parameter type checking, same as FastAPI path operations. Refactor incoming.