enable risc0 unstable feature and new precompiles

[eyusufatik]

Description

enables new precompiles.
in bitcoin-da replaces secp256k1 on the guest side with k256 crate, which has a new precompile.

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 77.0%. Comparing base (b62a598) to head (8417803).
Report is 1 commits behind head on esad/batch-proof-use-less-memory.

Files with missing lines	Patch %	Lines
crates/bitcoin-da/src/helpers/parsers.rs	71.4%	2 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
crates/bitcoin-da/src/helpers/builders/mod.rs	97.9% <100.0%> (+<0.1%)	⬆️
crates/bitcoin-da/src/helpers/mod.rs	88.2% <ø> (-0.7%)	⬇️
crates/bitcoin-da/src/helpers/parsers.rs	90.0% <71.4%> (-0.5%)	⬇️

... and 7 files with indirect coverage changes