fix(cache): use getOrCreateNote for reply linking to fix flaky thread test

Fixes #2001 — ThreadFilter test failed intermittently because
consumeTextNote used getNoteIfExists for reply-to linking. If the
reply event arrived before the root, the link was lost. Now uses
getOrCreateNote to create placeholders, same pattern as reposts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

desktopApp/src/jvmMain/kotlin/com/vitorpamplona/amethyst/desktop/cache/DesktopLocalCache.kt

@@ -228,7 +228,7 @@ class DesktopLocalCache : ICacheProvider {
         val note = getOrCreateNote(event.id)
         if (note.event != null) return false
         val author = getOrCreateUser(event.pubKey)
-        val repliesTo = event.tagsWithoutCitations().mapNotNull { getNoteIfExists(it) }
+        val repliesTo = event.tagsWithoutCitations().map { getOrCreateNote(it) }
         note.loadEvent(event, author, repliesTo)
         relay?.let { note.addRelay(it) }
         repliesTo.forEach { it.addReply(note) }