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>

neode-ui/src/stores/mesh.ts

@@ -382,13 +382,13 @@ export const useMeshStore = defineStore('mesh', () => {
     }
   }
 
-  async function sendContent(contactId: number, cid: string, caption?: string) {
+  async function sendContent(contactId: number, cid: string, caption?: string, peerOnion?: string) {
     try {
       sending.value = true
       error.value = null
       const res = await rpcClient.call<{ sent: boolean; message_id: number; cid: string; size: number }>({
         method: 'mesh.send-content',
-        params: { contact_id: contactId, cid, caption },
+        params: { contact_id: contactId, cid, caption, peer_onion: peerOnion },
       })
       if (res.sent) await fetchMessages()
       return res