feat(infra): migrate self-hosted backend to netralax.de

Move Supabase + LiveKit from the netralax.cloud VPS to a new netralax.de server. Adds the migration runbook (docs/), one-time move scripts (scripts/migrate/), and prod Caddy/LiveKit config templates (infra/). Repoints the desktop publish/changelog URLs and prod ops config to .de. JWT_SECRET + VAPID copied identically so already-installed clients keep working; the new server also serves the legacy .cloud hostnames.

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

apps/desktop/package.json

@@ -95,7 +95,7 @@
     "publish": [
       {
         "provider": "generic",
-        "url": "https://update.netralax.cloud/windows/"
+        "url": "https://update.netralax.de/windows/"
       }
     ]
   }