Refactor crypto package to use p256k1 signer

- Replaced the p256k package with p256k1.mleku.dev/signer across the codebase, updating all instances where the previous signer was utilized.
- Removed the deprecated p256k package, including all related files and tests, to streamline the codebase and improve maintainability.
- Updated various components, including event handling, database interactions, and protocol implementations, to ensure compatibility with the new signer interface.
- Enhanced tests to validate the new signing functionality and ensure robustness across the application.
- Bumped version to v0.23.3 to reflect these changes.

pkg/protocol/directory/directory_test.go

@@ -7,14 +7,14 @@ import (
 
 	"lol.mleku.dev/chk"
 	"next.orly.dev/pkg/crypto/ec/secp256k1"
-	"next.orly.dev/pkg/crypto/p256k"
+	p256k1signer "p256k1.mleku.dev/signer"
 	"next.orly.dev/pkg/encoders/bech32encoding"
 	"next.orly.dev/pkg/protocol/directory"
 )
 
-// Helper to create a test keypair using p256k.Signer
-func createTestKeypair(t *testing.T) (*p256k.Signer, []byte) {
-	signer := new(p256k.Signer)
+// Helper to create a test keypair using p256k1signer.P256K1Signer
+func createTestKeypair(t *testing.T) (*p256k1signer.P256K1Signer, []byte) {
+	signer := p256k1signer.NewP256K1Signer()
 	if err := signer.Generate(); chk.E(err) {
 		t.Fatalf("failed to generate keypair: %v", err)
 	}