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/views/AppDetails.vue

@@ -812,13 +812,6 @@ function launchApp() {
     'tailscale': { dev: 'http://localhost:8240', prod: 'http://localhost:8240' },
     'lnd': { dev: 'http://localhost:8081', prod: 'http://localhost:8081' },
     'bitcoin-knots': { dev: 'http://localhost:8334', prod: 'http://localhost:8334' },
-    'botfights': { dev: 'https://botfights.net', prod: 'https://botfights.net' },
-    'nwnn': { dev: 'https://nwnn.l484.com', prod: 'https://nwnn.l484.com' },
-    '484-kitchen': { dev: 'https://484.kitchen', prod: 'https://484.kitchen' },
-    'call-the-operator': { dev: 'https://cta.tx1138.com', prod: 'https://cta.tx1138.com' },
-    'arch-presentation': { dev: 'https://present.l484.com', prod: 'https://present.l484.com' },
-    'syntropy-institute': { dev: 'https://syntropy.institute', prod: 'https://syntropy.institute' },
-    't-zero': { dev: 'https://teeminuszero.net', prod: 'https://teeminuszero.net' }
   }
   
   if (appUrls[id]) {