Offer no Replay for a delivery to a deleted target (closes #387)

In the event log, a delivery to a deleted target still offered Replay, and pressing it answered "Recreate the target, then replay", advice that cannot work: a recreated target is a new one, and the old delivery still names the deleted one. Such a delivery now has no Replay button, and its row still names the target marked "(deleted)". The refusal, which a page loaded before the delete can still reach, now tells the operator to use Resubmit to send the event to the webhook's currently active targets.

Model: opus-5-5

internal/handlers/delivery_replay_test.go

@@ -513,7 +513,11 @@ func TestHandleSourceLogs_RendersReplayControlAndBanner(t *testing.T) {
 	)
 
 	assert.Contains(t, refused, "alert-error")
-	assert.Contains(t, refused, "has been deleted")
+	assert.Contains(
+		t, refused,
+		"has been deleted. Use Resubmit to send the event "+
+			"to the webhook",
+	)
 
 	// An outcome code nobody issued renders no banner at all.
 	unknown := renderSourceLogsPageWithQuery(