Added basics/close-account/poseidon

[ritikbhatt20]

Key Difference from other PR's: - Addition of the latest Poseidon library code, which includes a payer argument for init and initIfNeeded, ensuring compatibility with multi-signer configurations - previous PR’s had been defaulted to a single signer with only .init() function which will not work with new poseidon code now.

• added the close-account poseidon program in the /basics/close-account/poseidon directory.
• replaced all occurrences of yarn with pnpm
• wrote tests using both Solana Bankrun framework and Anchor native test
• executed pnpm fix
• commited pnpm-lock.yaml to the repository

[ritikbhatt20]

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!

gm @heyAyushh ,

I've completed the requested steps:

1. Merged main into my branch.
2. Ran pnpm fix.
3. Verified the implementation includes the transpiled Anchor program and TypeScript files.
4. Synchronized program ID
5. Ran cargo fmt and cargo clippy for Rust code quality.
6. Pushed all updates.

Please review again. Thank you!