docs: add examples to GETTING_STARTED.md for each framework adapter

[thewisecrab]

Difficulty: Easy
Expected outcome: Add a short code snippet for each supported framework (LangChain, CrewAI, AutoGen, etc.) showing how to connect it to AMC.

Currently docs/GETTING_STARTED.md lists adapters but doesn't show framework-specific examples. Each adapter should have a 3-5 line example.

Files to edit: docs/GETTING_STARTED.md