Add basics/hello-solana/poseidon

[jynkyv]

Adds a new example program demonstrating basic Solana program functionality using the Poseidon framework. The program implements a simple "Hello, Solana!" example that showcases:

• Basic instruction handling
• Error management with custom error types
• Clock usage demonstration
• Comprehensive test coverage

Features

• ✅ Basic Solana program structure
• ✅ Poseidon framework integration
• ✅ Custom error handling
• ✅ Timestamp logging
• ✅ Complete test suite

Testing

The program includes comprehensive testing:

• TypeScript integration tests
• Rust unit tests
• Bankrun tests for on-chain behavior verification

[heyAyushh]

Thanks for your submission! To verify the technical implementation, please complete these steps:

1. Merge the main branch into your PR to get the latest updates
2. Run pnpm fix at the project root for consistent code style
3. Ensure your implementation includes:
   • Transpiled Anchor program in the programs folder
   • TypeScript files in the ts-programs folder
4. Run poseidon sync to synchronize program ID and keys
5. Run cargo fmt and cargo clippy for Rust code quality
6. Push your changes

Please note: This review is to verify technical completeness of the submission

Let me know once you've completed these steps and I'll review again. Thanks!