fix: add DNS names to CSR and improve certificate generation

internal/pki/ca.go

@@ -123,6 +123,7 @@ func GenerateCertificateRequest(commonName, keyOutPath, csrOutPath string) error
 			Organization: []string{"KAT System"},
 		},
 		SignatureAlgorithm: x509.SHA256WithRSA,
+		DNSNames:           []string{commonName}, // Add the CN as a SAN
 	}
 
 	// Create CSR