feat(ui): dual-ecash wallet settings, buy-peer-files, seed backup, assorted fixes

- Tabbed Wallet Settings modal (Cashu + Fedimint) and dual-balance wallet card
- Buy a peer's paid file (ecash / node Lightning / on-chain / external QR)
- Recovery-phrase reveal + backup section; onboarding seed retry resilience
- NetBird HTTPS launch, remote-control two-finger scroll + external-open
- Shared BackButton, single-v version label, mesh Bitcoin header toggles

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

neode-ui/src/api/remote-relay.ts

@@ -139,6 +139,41 @@ function deepElementFromPoint(x: number, y: number): Element | null {
   return el
 }
 
+/**
+ * Find the nearest scrollable ancestor of `el` for the given delta, hopping out
+ * of same-origin iframes when needed. Synthetic WheelEvents are untrusted and
+ * never actually scroll the page, so two-finger scroll must call scrollBy on a
+ * real scroll container — this locates it (e.g. the right-hand app frame). (#7)
+ */
+function findScrollable(el: Element | null, dx: number, dy: number): Element | null {
+  let node: Element | null = el
+  let guard = 0
+  while (node && guard++ < 60) {
+    const win = node.ownerDocument?.defaultView
+    const style = win?.getComputedStyle(node)
+    if (style) {
+      const oy = style.overflowY
+      const ox = style.overflowX
+      const isRoot = node === node.ownerDocument?.scrollingElement
+      const canY =
+        (oy === 'auto' || oy === 'scroll' || isRoot) &&
+        node.scrollHeight > node.clientHeight + 1
+      const canX =
+        (ox === 'auto' || ox === 'scroll' || isRoot) &&
+        node.scrollWidth > node.clientWidth + 1
+      if ((dy !== 0 && canY) || (dx !== 0 && canX)) return node
+    }
+    if (node.parentElement) {
+      node = node.parentElement
+    } else if (win?.frameElement) {
+      node = win.frameElement as Element // same-origin iframe → continue in parent doc
+    } else {
+      break
+    }
+  }
+  return null
+}
+
 /** The actually-focused element, descending through same-origin iframes. */
 function deepActiveElement(): Element | null {
   let el: Element | null = document.activeElement
@@ -267,10 +302,19 @@ function handleMessage(data: string) {
       break
     }
     case 's': {
-      const dy = msg.y ?? 0
-      document.dispatchEvent(new WheelEvent('wheel', {
-        bubbles: true, deltaY: dy * 100, deltaMode: WheelEvent.DOM_DELTA_PIXEL,
-      }))
+      // Scroll the element under the virtual cursor (incl. inside same-origin
+      // app frames like the right-hand panel), not the top document. A synthetic
+      // wheel event won't scroll — call scrollBy on a real scroll container. (#7)
+      const dy = (msg.y ?? 0) * 100
+      const dx = (msg.x ?? 0) * 100
+      const start = deepElementFromPoint(cursorX, cursorY)
+      const scroller = findScrollable(start, dx, dy)
+      if (scroller) {
+        scroller.scrollBy({ left: dx, top: dy })
+      } else {
+        const win = start?.ownerDocument?.defaultView ?? window
+        win.scrollBy(dx, dy)
+      }
       break
     }
   }
@@ -308,6 +352,30 @@ function doConnect() {
   }
 }
 
+/**
+ * Ask the companion (phone) to open a URL in its own browser.
+ *
+ * "Open in external browser" apps can't be usefully opened on the kiosk when a
+ * companion is driving it — `window.open` lands on the kiosk, which the phone
+ * user never sees. When a companion is active we forward the URL over the relay
+ * socket ({"t":"o","url"}); the backend routes it to the phone, which opens it.
+ *
+ * Returns true if the request was forwarded (caller should NOT open locally),
+ * false if there's no active companion (caller should open normally).
+ */
+export function requestExternalOpen(url: string): boolean {
+  if (!url || !/^https?:\/\//i.test(url)) return false
+  if (!companionActive.value) return false
+  if (!ws || ws.readyState !== WebSocket.OPEN) return false
+  try {
+    ws.send(JSON.stringify({ t: 'o', url }))
+    if (import.meta.env.DEV) console.log('[RemoteRelay] Forwarded external-open to companion:', url)
+    return true
+  } catch {
+    return false
+  }
+}
+
 /** Start the remote relay listener. Connects to /ws/remote-relay. */
 export function startRemoteRelay() {
   shouldReconnect = true