dsh-remote 0.5.0: node settings, session-cookie edge auth, sign-in popup

- Settings → Remote devices → Node: type master|slave (stored in state, beats
  config role; Restart DSH button under systemd/launchd), origin (read-only:
  own origin / paired master), 'Master has an auth middleware' toggle
- middleware on: a non-DSH answer on the link (login redirect, 401/403, inline
  HTML) raises auth-required; the UI opens <master>/dsh-remote/signin in a popup,
  the user signs in to the proxy, one click hands the proxy session cookie back
  (postMessage, origin-checked, trusted origins only), link retries
- edge mode 'cookie': pasted authentik_proxy_… (or a whole Cookie header),
  rotated proxy cookies persisted back; pair.mjs/install-mac --edge cookie
- connectMaster serialised; a failed attempt never clears a finished link
- tests: cookie seed/mode, HTML login wall; e2e-signin against a fake proxy

lib/store.mjs

@@ -140,6 +140,16 @@ export class Store {
     return true
   }
 
+  // ---- UI-managed node settings ---------------------------------------------
+  /** { nodeType?: 'master'|'slave', authMiddleware?: boolean } — set from Settings → Remote devices. */
+  settings() { return (this.data.settings ||= {}) }
+
+  setSettings(patch) {
+    this.data.settings = { ...this.settings(), ...patch }
+    this.save()
+    return this.data.settings
+  }
+
   // ---- slave side: link to master ------------------------------------------
   get master() { return this.data.master || null }