fix(mesh): resolve ContentRef peer via DID + name-match fallback

Mesh peer pubkeys (LoRa advert ed25519) differ from federation node
pubkeys (archipelago identity), so matching on pubkey always missed
and attachments >160B had no transport. Match on master DID instead;
also accept an explicit peer_onion override from the frontend, which
resolves the peer by display name against federation.list-nodes.

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

core/archipelago/src/mesh/mod.rs

@@ -601,17 +601,31 @@ impl MeshService {
         wire: Vec<u8>,
     ) -> Result<()> {
         let envelope = crate::mesh::message_types::TypedEnvelope::from_wire(&wire)?;
-        // Find the contact_id by pubkey match; fall back to synthetic.
+        // The sender's `from_pubkey_hex` is their archipelago identity key,
+        // which differs from the mesh peer's LoRa advert pubkey. Resolve
+        // identity → DID → mesh contact_id via federation/nodes.json (the
+        // DID is the only stable cross-transport key).
+        let federation_did = {
+            let nodes = crate::federation::load_nodes(&self.data_dir)
+                .await
+                .unwrap_or_default();
+            nodes
+                .into_iter()
+                .find(|n| n.pubkey == from_pubkey_hex)
+                .map(|n| n.did)
+        };
         let contact_id = {
             let peers = self.state.peers.read().await;
             peers
                 .iter()
                 .find_map(|(cid, p)| {
-                    if p.pubkey_hex.as_deref() == Some(from_pubkey_hex) {
-                        Some(*cid)
-                    } else {
-                        None
-                    }
+                    let did_match = federation_did
+                        .as_ref()
+                        .zip(p.did.as_ref())
+                        .map(|(a, b)| a == b)
+                        .unwrap_or(false);
+                    let pk_match = p.pubkey_hex.as_deref() == Some(from_pubkey_hex);
+                    if did_match || pk_match { Some(*cid) } else { None }
                 })
                 .unwrap_or_else(|| {
                     let bytes = hex::decode(from_pubkey_hex).unwrap_or_default();