feature: payments capability for agents powered by x402

[raihankhan-rk]

Proposed Changes

Integrated payment capabilities for agents to enable agentic commerce powered by x402. Agents can now discover, buy/sell services/data directly to any other agent built using uAgents framework

Linked Issues

[PROPOSAL] Integrate x402 (x402.dev) for enabling agentic commerce #771

Types of changes

What type of change does this pull request make (put an x in the boxes that apply)?

• Bug fix (non-breaking change that fixes an issue).
• New feature added (non-breaking change that adds functionality).
• Breaking change (fix or feature that would cause existing functionality to stop working as expected).
• Documentation update.
• Something else (e.g., tests, scripts, example, deployment, infrastructure).

Checklist

Put an x in the boxes that apply:

• I have read the CONTRIBUTING guide
• Checks and tests pass locally

If applicable

• I have added tests that prove my fix is effective or that my feature works
• I have added/updated the documentation (executed the script in python/scripts/generate_api_docs.py)

Further comments

uAgents is an excellent framework to build agents that can natively communicate with each other on the agentverse but it lacked one core concept: commerce

Agents did not have any capability to transact with each other which killed the entire scope of Agentic economy and renders the motivation for building effective quality agents to nearly zero.

With x402 integration, I've added support for payment capability which is as simple as 3 lines of code and lets agents to buy/sell data or services to each other autonomously building a complete autonomous agentic ecosystem.

For more info, please refer to the README.md committed in the PR