Enhance relay testing and event handling

- Updated TestRelay to include a wait mechanism for relay readiness, improving test reliability.
- Refactored startTestRelay to return the assigned port, allowing dynamic port assignment.
- Added timestamp validation in HandleEvent to reject events with timestamps more than one hour in the future.
- Introduced channels for handling OK and COUNT messages in the Client struct, improving message processing.
- Updated tests to reflect changes in event timestamp handling and increased wait times for event processing.
- Bumped version to v0.20.6 to reflect these enhancements.

relay-tester/keys.go

@@ -91,7 +91,8 @@ func CreateEphemeralEvent(signer *p256k.Signer, kindNum uint16, content string)
 func CreateDeleteEvent(signer *p256k.Signer, eventIDs [][]byte, reason string) (ev *event.E, err error) {
 	tags := tag.NewS()
 	for _, id := range eventIDs {
-		tags.Append(tag.NewFromBytesSlice([]byte("e"), id))
+		// e tags must contain hex-encoded event IDs
+		tags.Append(tag.NewFromBytesSlice([]byte("e"), []byte(hex.Enc(id))))
 	}
 	if reason != "" {
 		tags.Append(tag.NewFromBytesSlice([]byte("content"), []byte(reason)))