docs: add AI solution disclaimer

[Harmanpreet-Microsoft]

Added a disclaimer regarding AI solutions and associated risks.

Purpose

This pull request adds a disclaimer to the README.md to inform users about their responsibility when using AI solutions created with the provided templates.

Documentation update:

• Added a disclaimer section to the README.md stating user responsibility for risk assessment and compliance with laws and safety standards, and providing links to transparency documents for Agent Service and Agent Framework.* ...

Does this introduce a breaking change?

• Yes
• No

Golden Path Validation

• I have tested the primary workflows (the "golden path") to ensure they function correctly without errors.

Deployment Validation

• I have validated the deployment process successfully and all services are running as expected with this change.

What to Check

Verify that the following are valid

• I have built and tested the code locally and in a deployed app
• For frontend changes, I have pulled the latest code from main, built the frontend, and committed all static files.
• This is a change for all users of this app. No code or asset is specific to my use case or my organization.

Other Information