fix(wallet): Minibits default Cashu mint, resilient peer-file invoices, named default federation

- Cashu default mint was the local Fedimint guardian (:8175), wrongly surfacing
  a Fedimint URL in the Cashu mints list. Default is now Minibits
  (https://mint.minibits.cash/Bitcoin) — Cashu and Fedimint are distinct
  protocols (Fedimint lives under its own tab).
- Peer-file (buy) invoice creation: retry the LND REST call (3× / 400ms) so a
  transient LND-REST blip (swap pressure / just-restarted / TLS race) no longer
  hard-fails as an opaque 503, and surface the real error chain ({:#}) in the
  response + logs instead of a generic "Failed to create invoice".
- Autojoined default federation now shows a friendly name ("Archipelago
  Federation") in the Fedimint tab instead of a bare federation id.

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

neode-ui/src/views/Mesh.vue

@@ -884,6 +884,17 @@ function scrollChatToBottom() {
   }
 }
 
+// Wheel over the chat must scroll ONLY the chat — never leak to the contacts
+// list or the page. CSS overscroll-behavior wasn't enough (the leak happens
+// even when the chat doesn't overflow), so consume the wheel and apply it to
+// the chat container directly. Used with `@wheel.prevent` so the default
+// (page/contacts) scroll never fires.
+function onChatWheel(e: WheelEvent) {
+  const el = chatScrollEl.value
+  if (!el) return
+  el.scrollTop += e.deltaY
+}
+
 async function handleBroadcast() {
   broadcasting.value = true
   try { await mesh.broadcastIdentity() } finally { broadcasting.value = false }
@@ -1593,7 +1604,7 @@ function isImageMime(mime?: string): boolean {
                 <span v-if="activeChatPeer" class="mesh-chat-header-time">{{ timeAgo(activeChatPeer.last_heard) }}</span>
               </div>
             </div>
-            <div ref="chatScrollEl" class="mesh-chat-messages" @scroll="scheduleReadReceipt">
+            <div ref="chatScrollEl" class="mesh-chat-messages" @scroll="scheduleReadReceipt" @wheel.prevent="onChatWheel">
               <div v-if="chatMessages.length === 0" class="mesh-chat-no-messages">
                 No messages yet. Say hello!
               </div>