nostrdb/tce: add AUTH to-client-event

This was committed to damus, but this should be in nostrdb or else we
will lose it when we update.

Damus: 84cfeb1604 ("nip42: add initial relay auth support")
Link: https://groups.google.com/a/damus.io/g/patches/c/Zx3dk01e0yg/m/t59TsVkXAQAJ
Signed-off-by: Charlie Fish <contact@charlie.fish>
Signed-off-by: William Casarin <jb55@jb55.com>

nostrdb/src/nostrdb.h

@@ -91,6 +91,7 @@ enum tce_type {
 	NDB_TCE_OK     = 0x2,
 	NDB_TCE_NOTICE = 0x3,
 	NDB_TCE_EOSE   = 0x4,
+	NDB_TCE_AUTH   = 0x5,
 };
 
 enum ndb_ingest_filter_action {