Bitcoin payment instructions switch

[Camillarhi]

This PR integrates the bitcoin_payment_instructions crate while maintaining backward compatibility:

• Integrated bitcoin_payment_instructions crate for better payment URI parsing
• Maintained sync API while using Tokio's runtime internally
• Kept existing payment fallback logic (BOLT12 → BOLT11 → Onchain)
• Added proper error handling for new parser

Fixes #521

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[tnull]

Thanks for your interest in this! As mentioned over at #521, I think it however makes sense to do this as part of/after the ongoing HRN work. So unfortunately I don't think it makes sense to just switch parts of the code over before we do the HRN integration. Going ahead and closing this.