chore: dev environment — signet testnet stack, mock LND RPCs, faucet button

Switch docker-compose from regtest to signet, add standalone testnet stack
(docker-compose.testnet.yml) with Bitcoin+LND+ThunderHub+Fedimint. Mock
backend now auto-detects Podman/Docker sockets and includes full LND/Lightning
RPC mocks. Dev scripts refactored with boot mode, testnet option, and macOS
EAGAIN fix for port cleanup. Added dev faucet button to Home.vue.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/dev-dist/sw.js

@@ -82,7 +82,7 @@ define(['./workbox-21a80088'], (function (workbox) { 'use strict';
     "revision": "3ca0b8505b4bec776b69afdba2768812"
   }, {
     "url": "index.html",
-    "revision": "0.qj72pfa74qs"
+    "revision": "0.g6vfn35hb3c"
   }], {});
   workbox.cleanupOutdatedCaches();
   workbox.registerRoute(new workbox.NavigationRoute(workbox.createHandlerBoundToURL("index.html"), {