fix(relayauth): exclude event author from NOTIFY_INBOX counterparties

A pending non-gift-wrap event's `p` tags are the people it notifies, but
some events self-p-tag the author. Drop the author's own key so the auth
reason and follow-trust check reflect who is actually being notified, not
the sender. (Own-relay over-attribution is already handled upstream by the
isInMyRelayList allow.) Adds a regression test.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EZjmYpgHP4pf79Sav5QT8a

amethyst/src/main/java/com/vitorpamplona/amethyst/service/relayClient/authCommand/model/RelayAuthPurposeDeriver.kt

@@ -49,7 +49,9 @@ object RelayAuthPurposeDeriver {
             if (event.kind == GiftWrapEvent.KIND) {
                 dmRecipients.addAll(pTags)
             } else {
-                notifyRecipients.addAll(pTags)
+                // We're notifying the people the event references, not its author — drop the
+                // author's own key so a self-p-tag doesn't read as "notify yourself".
+                notifyRecipients.addAll(pTags - event.pubKey)
             }
         }
 

amethyst/src/test/java/com/vitorpamplona/amethyst/service/relayClient/authCommand/model/RelayAuthPurposeDeriverTest.kt

@@ -63,6 +63,16 @@ class RelayAuthPurposeDeriverTest {
         assertEquals(setOf(alice, bob), purposes[0].counterparties)
     }
 
+    @Test
+    fun notifyExcludesTheEventsOwnAuthor() {
+        val author = "11".repeat(32) // matches event()'s pubKey
+        val purposes = RelayAuthPurposeDeriver.derive(listOf(event(1, listOf(author, alice))), emptyMap())
+
+        assertEquals(1, purposes.size)
+        assertEquals(AuthPurposeKind.NOTIFY_INBOX, purposes[0].kind)
+        assertEquals(setOf(alice), purposes[0].counterparties)
+    }
+
     @Test
     fun subscriptionAuthorsBecomeReadOutbox() {
         val purposes = RelayAuthPurposeDeriver.derive(emptyList(), mapOf("sub1" to listOf(Filter(authors = listOf(alice, bob)))))