feat(chain): introduce/build a bindex-rs PoC

[oleonardolima]

Describe the enhancement

I recently came across https://github.com/romanz/bindex-rs during some discussion in Floresta Retreat.

As per the slides linked in it's README, there's some good improvements when benchmarked against other blockchain indexers implementations and I think it would be an interesting idea to play with it and come up with a PoC of integrating it to BDK, if it's even possible.

Use case

Impact

• Blocking production usage
• Nice-to-have / UX improvement
• Developer experience / maintainability

Are you using BDK in a production project?

• Yes
• No
• Not yet, but planning to (NOTE: the bindex-rs project does not have any BDK integration AFAIK)

Which backend(s) are relevant (if any)?

• Electrum
• Esplora
• Bitcoin Core RPC
• None / not backend-related (e.g. bdk_chain, bdk_core)
• Other (please specify): A new backend implementation that integrates with bindex-rs

Project or organization (optional)

Additional context

[Aniket-pd]

I like this direction. bindex-rs seems promising, and a small PoC could help us understand how cleanly it aligns with BDK’s chain data model