fix: resolve did:dht compilation errors

- Simplify DHT encoding: use JSON instead of DNS packets (drop simple-dns)
- Fix mainline crate API: SigningKey takes 32 bytes, get_mutable returns Result
- Add missing dht_did field to IdentityRecord constructor
- Store DID Document as JSON in DHT (DNS encoding deferred)

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

neode-ui/src/locales/en.json

@@ -322,6 +322,7 @@
     "subtitle": "Discover and install apps for your new sovereign life",
     "curatedTab": "Curated",
     "communityTab": "Community",
+    "nostrCommunityTab": "Nostr Community",
     "filterByCategory": "Filter by Category",
     "searchPlaceholder": "Search apps...",
     "downloading": "Downloading...",
@@ -376,6 +377,7 @@
     "manageDomains": "Manage Domains",
     "relaysConnected": "{count} connected",
     "peersKnown": "{count} peer(s) known",
+    "findNodes": "Find Nodes",
     "sendMessage": "Send Message",
     "sendMessageTitle": "Send Message (over Tor)",
     "to": "To",