feat: add Peer Files UI for browsing and downloading federated content

- New PeerFiles.vue view shows federated peers and their shared catalogs
- Peer Files card in Cloud.vue shows when federation peers exist
- New content.download-peer RPC fetches content from peer via Tor
- Route: /dashboard/cloud/peers

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

core/archipelago/src/api/rpc/mod.rs

@@ -417,6 +417,7 @@ impl RpcHandler {
             "content.set-pricing" => self.handle_content_set_pricing(params).await,
             "content.set-availability" => self.handle_content_set_availability(params).await,
             "content.browse-peer" => self.handle_content_browse_peer(params).await,
+            "content.download-peer" => self.handle_content_download_peer(params).await,
 
             // DWN (Decentralized Web Node)
             "dwn.status" => self.handle_dwn_status().await,