fix: resolve WebSocket failure and crypto.randomUUID crash on HTTP/LXC

- Replace crypto.randomUUID() with a polyfill (generateUUID) that falls
  back to crypto.getRandomValues or Math.random — fixes crash on HTTP
  non-secure contexts where randomUUID is unavailable
- Fix WebSocket URL hardcoding port 8000 — use window.location.host so
  connections go through Nginx proxy in Docker/LXC instead of bypassing it
- Add /api/v1/status/ws/ location block in nginx.conf with WebSocket
  upgrade headers (must precede /api/ to avoid missing Upgrade header)

frontend/src/hooks/useStatusPolling.ts

@@ -23,8 +23,8 @@ export function useStatusPolling() {
     if (STANDALONE || !isAuthenticated || !token) return
 
     const protocol = window.location.protocol === 'https:' ? 'wss' : 'ws'
-    const host = window.location.hostname
-    const url = `${protocol}://${host}:8000/api/v1/status/ws/status?token=${encodeURIComponent(token)}`
+    const host = window.location.host  // includes port when non-standard
+    const url = `${protocol}://${host}/api/v1/status/ws/status?token=${encodeURIComponent(token)}`
 
     const ws = new WebSocket(url)
     wsRef.current = ws