feat: upgrade crypto ecosystem to latest RustCrypto stack (#1)

Upgrade all core cryptographic dependencies to their latest versions:

Dependencies:
- digest: 0.10 to 0.11
- elliptic-curve: 0.13 to 0.14
- hkdf: 0.12 to 0.13
- hmac: 0.12 to 0.13
- rand: 0.8 to 0.10
- rand_chacha: 0.3 to 0.10
- sha2: 0.10 to 0.11
- getrandom: 0.2 to 0.4 (WASM)
- ml-kem: 0.3.0-rc.0 to 0.3
- ecdsa: 0.16 to 0.17.0-rc.23
- rfc6979: 0.4 to 0.6 (now internal to ecdsa)
- p256/p384/p521: 0.13 to 0.14.0-rc.15
- curve25519-dalek: 4 to 5.0.0-rc
- ed25519-dalek: 2 to 3.0.0-rc
- cryptoki: 0.9 to 0.12
- rustyline: 17 to 18
- scrypt: 0.11 to 0.12
- voprf replaced by voprf-vx 1.0.0-pre.0

Migration changes:
- generic-array 0.14 to 1.4 with hybrid-array 0.4 interop
- ArrayLength<u8> to ArrayLength (generic-array 1.x)
- Added ConcatExt trait to disambiguate from [T]::concat
- Replaced Hmac with SimpleHmac for digest 0.11 compatibility
- Added OutputSize<H>: ArrayLength bounds throughout Hash trait
- Converted hybrid_array::Array between GenericArray at API boundaries
- Updated GroupEncoding Repr bound to hybrid_array::Array
- ECDSA sign now uses ecdsa::hazmat::sign_prehashed_rfc6979
- Removed direct rfc6979 dependency (handled by ecdsa internally)
- Replaced bincode with postcard for no_std serialization
- Re-exported hybrid_array from crate root

Other changes:
- Renamed crate to opaque-vx
- Increased MSRV to 1.89
- Added cryptography to Cargo.toml categories
- Removed Facebook-specific contributions from CONTRIBUTING.md
- Removed v3 to v4 migration test
- Removed unstable rustfmt configurations for stable compatibility

Reviewed-on: #1
Co-authored-by: UneBaguette <[email protected]>
Co-committed-by: UneBaguette <[email protected]>

src/tests/mock_rng.rs

@@ -9,9 +9,10 @@
 use core::cmp::min;
 use std::vec::Vec;
 
-use rand::{CryptoRng, Error, RngCore};
+use core::convert::Infallible;
+use rand_core::{TryCryptoRng, TryRng};
 
-/// A simple implementation of `RngCore` for testing purposes.
+/// A simple implementation of `Rng` for testing purposes.
 ///
 /// This generates a cyclic sequence (i.e. cycles over an initial buffer)
 #[derive(Clone, Debug)]
@@ -38,29 +39,35 @@ fn rotate_left<T>(data: &mut [T], steps: usize) {
     data.reverse();
 }
 
-impl RngCore for CycleRng {
-    fn next_u32(&mut self) -> u32 {
-        unimplemented!()
+impl TryRng for CycleRng {
+    type Error = Infallible;
+
+    fn try_next_u32(&mut self) -> Result<u32, Self::Error> {
+        let mut buf = [0u8; 4];
+
+        self.try_fill_bytes(&mut buf)?;
+
+        Ok(u32::from_le_bytes(buf))
     }
 
-    #[inline]
-    fn next_u64(&mut self) -> u64 {
-        unimplemented!()
+    fn try_next_u64(&mut self) -> Result<u64, Self::Error> {
+        let mut buf = [0u8; 8];
+
+        self.try_fill_bytes(&mut buf)?;
+
+        Ok(u64::from_le_bytes(buf))
     }
 
-    #[inline]
-    fn fill_bytes(&mut self, dest: &mut [u8]) {
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Self::Error> {
         let len = min(self.v.len(), dest.len());
-        dest[..len].copy_from_slice(&self.v[..len]);
-        rotate_left(&mut self.v, len);
-    }
 
-    #[inline]
-    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
-        self.fill_bytes(dest);
+        dest[..len].copy_from_slice(&self.v[..len]);
+
+        rotate_left(&mut self.v, len);
+
         Ok(())
     }
 }
 
 // This is meant for testing only
-impl CryptoRng for CycleRng {}
+impl TryCryptoRng for CycleRng {}