fix: correct C bool comparison in blake3 CGO

- Use bool() cast instead of != 0 for C bool type

aead/aead.go

@@ -7,7 +7,7 @@ import (
 	"errors"
 	"fmt"
 
-	"crypto/chacha20poly1305"
+	"golang.org/x/crypto/chacha20poly1305"
 )
 
 // AeadID identifies an AEAD algorithm

hash/blake3/blake3_cgo.go

@@ -42,7 +42,7 @@ const (
 
 var (
 	// useGPU indicates if GPU acceleration is available
-	useGPU = C.crypto_gpu_available() != 0
+	useGPU = bool(C.crypto_gpu_available())
 )
 
 // GPUAvailable returns true if GPU acceleration is available.

kem/x25519.go

@@ -5,7 +5,7 @@ import (
 	"crypto/subtle"
 	"errors"
 
-	"crypto/curve25519"
+	"golang.org/x/crypto/curve25519"
 )
 
 // X25519Impl implements X25519 as a KEM