refactor(commons): share NIP-59 gift-wrap+seal unwrap helper

Three call sites did the same two-layer peel —
  kind:1059 → (nip44 decrypt) → kind:13 sealed rumor → (nip44 decrypt) → rumor

Extracted as `GiftWrapEvent.unwrapAndUnsealOrNull(signer)` in
commons/relayClient/nip17Dm/, and collapsed:

- commons/marmot/MarmotIngest.kt — was an inline `when` switch; now a
  one-liner. Behaviour unchanged (still passes through if the inner
  isn't a seal, matching the previous defensive `else -> inner` branch).
- desktopApp/Main.kt — dropped the nested unwrap/unseal block in the
  kind:1059 case of the LocalCache dispatcher.
- cli/DmCommands.kt — replaced the manual chain in `decryptChatMessages`.

Android's DecryptAndIndexProcessor keeps its two separate handlers
(processNewGiftWrap / processNewSealedRumor) because the LocalCache
pipeline re-enters on each peel — that's a different shape and not
touched.

No behaviour change on any platform.

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/marmot/MarmotIngest.kt

@@ -20,6 +20,7 @@
  */
 package com.vitorpamplona.amethyst.commons.marmot
 
+import com.vitorpamplona.amethyst.commons.relayClient.nip17Dm.unwrapAndUnsealOrNull
 import com.vitorpamplona.quartz.marmot.GroupEventResult
 import com.vitorpamplona.quartz.marmot.MarmotInboundProcessor
 import com.vitorpamplona.quartz.marmot.WelcomeResult
@@ -27,7 +28,6 @@ import com.vitorpamplona.quartz.marmot.mip02Welcome.WelcomeEvent
 import com.vitorpamplona.quartz.marmot.mip03GroupMessages.GroupEvent
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
-import com.vitorpamplona.quartz.nip59Giftwrap.seals.SealedRumorEvent
 import com.vitorpamplona.quartz.nip59Giftwrap.wraps.GiftWrapEvent
 
 /**
@@ -96,19 +96,12 @@ suspend fun MarmotManager.ingest(event: Event): MarmotIngestResult =
 
 private suspend fun MarmotManager.ingestGiftWrap(wrap: GiftWrapEvent): MarmotIngestResult =
     try {
-        // NIP-59 wraps contain TWO encryption layers:
-        //   kind:1059 gift wrap → kind:13 sealed rumor → the rumor itself.
-        // `GiftWrapEvent.unwrapOrNull` only peels the outer layer; when the
-        // result is a [SealedRumorEvent] we must unseal it to reach the
-        // kind:444 Welcome rumor. The old code checked `isWelcomeEvent` on
-        // the seal (kind:13) and always took the Ignored branch, which is
-        // why every inbound Welcome was silently dropped by the CLI and by
-        // any non-Amethyst consumer.
-        val rumor =
-            when (val inner = wrap.unwrapOrNull(signer) ?: return MarmotIngestResult.Ignored) {
-                is SealedRumorEvent -> inner.unsealOrNull(signer) ?: return MarmotIngestResult.Ignored
-                else -> inner
-            }
+        // NIP-59 wraps carry two encryption layers (kind:1059 → kind:13 → rumor).
+        // [unwrapAndUnsealOrNull] peels both so we land directly on the inner
+        // kind:444 Welcome rumor. Checking `isWelcomeEvent` on the seal itself
+        // (the old bug) always took the Ignored branch and silently dropped
+        // every inbound Welcome.
+        val rumor = wrap.unwrapAndUnsealOrNull(signer) ?: return MarmotIngestResult.Ignored
         if (!MarmotInboundProcessor.isWelcomeEvent(rumor) || rumor !is WelcomeEvent) {
             return MarmotIngestResult.Ignored
         }

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/relayClient/nip17Dm/GiftWrapDecryptor.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.commons.relayClient.nip17Dm
+
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip59Giftwrap.seals.SealedRumorEvent
+import com.vitorpamplona.quartz.nip59Giftwrap.wraps.GiftWrapEvent
+
+/**
+ * Fully decrypt a NIP-59 gift wrap down to the inner rumor.
+ *
+ * A gift wrap carries two encryption layers:
+ *   kind:1059 [GiftWrapEvent] → kind:13 [SealedRumorEvent] → the rumor.
+ *
+ * [GiftWrapEvent.unwrapOrNull] peels only the outer layer. Every non-Android
+ * consumer that looks at the rumor directly (the CLI's `dm list`, the desktop
+ * chat receive path, the Marmot welcome ingest in commons) needs both peels.
+ *
+ * If the inner content isn't a [SealedRumorEvent] (malformed, or a future
+ * NIP-59 variant that wraps a rumor directly), the outer unwrap result is
+ * returned as-is so callers can still route on kind. Either unwrap returning
+ * null propagates as null.
+ */
+suspend fun GiftWrapEvent.unwrapAndUnsealOrNull(signer: NostrSigner): Event? {
+    val inner = unwrapOrNull(signer) ?: return null
+    return if (inner is SealedRumorEvent) inner.unsealOrNull(signer) else inner
+}