fix(ui): backoff remote-relay reconnects + stop cryptpad icon 404

Two console-noise fixes from a live error dump:
- remote-relay.ts reconnected on a FIXED 5s interval with no backoff, so when
  the backend is briefly down it floods the console/network with failed-WS
  attempts for the whole outage. It's a secondary feature (companion input), so
  add exponential backoff 1s->30s (mirrors websocket.ts), reset on open/start.
- cryptpad's catalog/marketplace entries pointed at a non-existent
  /assets/img/app-icons/cryptpad.webp -> a 404 on every marketplace render.
  Point it at the existing default icon (handleImageError swapped to it anyway).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

neode-ui/src/views/discover/curatedApps.ts

@@ -85,7 +85,7 @@ export function getCuratedAppList(): MarketplaceApp[] {
     { id: 'grafana', title: 'Grafana', version: '10.2.0', description: 'Analytics and monitoring platform. Dashboards for your node metrics and system health.', icon: '/assets/img/app-icons/grafana.png', author: 'Grafana Labs', dockerImage: `${R}/grafana:10.2.0`, repoUrl: 'https://github.com/grafana/grafana' },
     { id: 'searxng', title: 'SearXNG', version: '2024.1.0', description: 'Privacy-respecting metasearch engine. Search the internet without being tracked or profiled.', icon: '/assets/img/app-icons/searxng.png', author: 'SearXNG', dockerImage: `${R}/searxng:latest`, repoUrl: 'https://github.com/searxng/searxng' },
     { id: 'ollama', title: 'Ollama', version: '0.5.4', description: 'Run AI models locally. Llama, Mistral, and more — on your hardware, completely private.', icon: '/assets/img/app-icons/ollama.png', author: 'Ollama', dockerImage: `${R}/ollama:latest`, repoUrl: 'https://github.com/ollama/ollama' },
-    { id: 'cryptpad', title: 'CryptPad', version: '2024.12.0', description: 'End-to-end encrypted documents, spreadsheets, and presentations. Zero-knowledge collaboration.', icon: '/assets/img/app-icons/cryptpad.webp', author: 'XWiki SAS', dockerImage: `${R}/cryptpad:2024.12.0`, repoUrl: 'https://github.com/cryptpad/cryptpad' },
+    { id: 'cryptpad', title: 'CryptPad', version: '2024.12.0', description: 'End-to-end encrypted documents, spreadsheets, and presentations. Zero-knowledge collaboration.', icon: '/assets/icon/favico-black-v2.svg', author: 'XWiki SAS', dockerImage: `${R}/cryptpad:2024.12.0`, repoUrl: 'https://github.com/cryptpad/cryptpad' },
     { id: 'nextcloud', title: 'Nextcloud', version: '29', description: 'Your own private cloud. File sync, calendars, contacts — all on your hardware.', icon: '/assets/img/app-icons/nextcloud.webp', author: 'Nextcloud', dockerImage: `${R}/nextcloud:29`, repoUrl: 'https://github.com/nextcloud/server' },
     { id: 'vaultwarden', title: 'Vaultwarden', version: '1.30.0', description: 'Self-hosted password vault. Bitwarden-compatible with zero-knowledge encryption.', icon: '/assets/img/app-icons/vaultwarden.webp', author: 'Vaultwarden', dockerImage: `${R}/vaultwarden:1.30.0-alpine`, repoUrl: 'https://github.com/dani-garcia/vaultwarden' },
     { id: 'jellyfin', title: 'Jellyfin', version: '10.8.13', description: 'Free media server. Stream your movies, music, and photos to any device.', icon: '/assets/img/app-icons/jellyfin.webp', author: 'Jellyfin', dockerImage: `${R}/jellyfin:10.8.13`, repoUrl: 'https://github.com/jellyfin/jellyfin' },

neode-ui/src/views/marketplace/marketplaceData.ts

@@ -234,7 +234,7 @@ export function getCuratedAppList(): MarketplaceApp[] {
       title: 'CryptPad',
       version: '2024.12.0',
       description: 'End-to-end encrypted documents, spreadsheets, and presentations. Zero-knowledge collaboration.',
-      icon: '/assets/img/app-icons/cryptpad.webp',
+      icon: '/assets/icon/favico-black-v2.svg',
       author: 'XWiki SAS',
       dockerImage: `${REGISTRY}/cryptpad:2024.12.0`,
       manifestUrl: undefined,