[Feat]: Add Solana support for python SDK

[HealthyBuilder]

Is your feature request related to a problem? Please describe.

Can someone creates a new branch called "solana-demo", as @Woody4618 and I added Solana support for the demo but it requires a specific x402 version "x402 @ git+https://github.com/Woody4618/x402@solana-python#subdirectory=python/x402" for now.

We'll add the Solana support to this branch until x402 repo approved our PR for x402 Solana Support coinbase/x402#607. By that time we'll merge into main.

Here is the change:
Solana-ZH@bbd1e66

Describe the solution you'd like

Add Solana Support

Describe alternatives you've considered

No response

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[HealthyBuilder]

Or can I get added into people so that I can create a solana-demo branch. Many thanks

[lingzhong]

Hello @HealthyBuilder , can you share more details into

1. the purpose of the Solana branch if the main x402 accepts the Solana payment scheme submission
2. is this issue still needed, given the issue creation was 3 months ago

Thank you.