Feat: add observability support with Langfuse integration

[Pederzh]

Description

This PR introduces observability capabilities to the MCP (Model Context Protocol) agent,
allowing developers to track and monitor agent interactions through external observability
platforms.

Changes Made

• Added a flexible observability manager that supports multiple providers
• Integrated Langfuse as the primary observability platform for tracking LLM interactions
• Created comprehensive observability documentation
• Initially added Laminar support but removed it due to ESM compatibility issues
• Updated the MCP agent to support observability callbacks throughout its lifecycle

Fixes #(issue)

Type of change

• New feature (non-breaking change which adds functionality)