build(deps): align RustCrypto ECC dependency versions and remove unnecessary transitive pins

[Copilot]

RustCrypto’s ECC stack was still on older RC-era constraints. This PR updates the direct ECC dependencies to a compatible newer set and removes transitive pins that are no longer needed, letting Cargo resolve those crates naturally (including stable elliptic-curve).

• Direct dependency alignment

  • p256/p384/p521 → =0.14.0-rc.14
  • primeorder → =0.14.0-rc.14
  • ecdsa → =0.17.0-rc.22
  • ed25519-dalek/x25519-dalek → =3.0.0-rc.1
  • curve25519-dalek → =5.0.0-rc.1

• Transitive pin cleanup

  • Removed now-unnecessary transitive pins from picky/Cargo.toml (including elliptic-curve, primefield, and related transitive trait crates), per review feedback.

• Code compatibility adjustment

  • Added SignatureEncoding trait import in Ed25519 signing code so to_vec() remains available with the resolved dependency graph.

• Lockfile refresh

  • Regenerated root and wasm lockfiles to capture the cleaned dependency graph.

# picky/Cargo.toml (excerpt)

p256 = { version = "=0.14.0-rc.14", features = ["ecdh"] }
p384 = { version = "=0.14.0-rc.14", features = ["ecdh"] }
p521 = { version = "=0.14.0-rc.14", features = ["ecdh"] }
ecdsa = "=0.17.0-rc.22"
primeorder = "=0.14.0-rc.14"

# (unneeded transitive pins removed)

[Benoît Cortier (CBenoit)]

Copilot Remove any dependency that we don’t need to pin anymore.

[Copilot]

Done in 3bd6247.
I removed the unneeded transitive RustCrypto pins from picky/Cargo.toml and refreshed both lockfiles accordingly.

[Benoît Cortier (CBenoit)]

Copilot removed pins that are still required. I’ll do the final edits myself.