fix(ui): trim verbose startup notice; show daemon output on shutdown for external daemons

- Loading "taking longer than expected" notice: shorten the body + hint so the
  startup screen reads less wordy (same info, ~half the text).
- Shutdown screen: when the wallet attached to an EXTERNAL daemon (no captured
  stdout — debug_log_path_ is only set when we spawn it), the "dragonxd output"
  panel was always empty, leaving just a spinner. Fall back to tailing the
  daemon's debug.log so the user can watch the node flush the block index and
  exit. Adds App::tailDaemonDebugLog() (best-effort, reads only the file tail).

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

src/app.cpp

@@ -5742,6 +5742,39 @@ void App::beginShutdown()
     });
 }
 
+std::vector<std::string> App::tailDaemonDebugLog(int maxLines) const
+{
+    std::vector<std::string> out;
+    if (maxLines <= 0) return out;
+    const std::string path = util::Platform::getDataDir() + "debug.log";
+    std::error_code ec;
+    const auto sz = std::filesystem::file_size(path, ec);
+    if (ec || sz == 0) return out;
+    std::ifstream f(path, std::ios::binary);
+    if (!f) return out;
+
+    // Read only the last ~16 KB — plenty for a handful of lines, cheap even for a multi-GB log.
+    const std::uintmax_t kTailBytes = 16 * 1024;
+    const std::uintmax_t start = sz > kTailBytes ? sz - kTailBytes : 0;
+    f.seekg(static_cast<std::streamoff>(start), std::ios::beg);
+    std::string chunk(static_cast<std::size_t>(sz - start), '\0');
+    f.read(&chunk[0], static_cast<std::streamsize>(chunk.size()));
+    chunk.resize(static_cast<std::size_t>(f.gcount()));
+
+    std::vector<std::string> lines;
+    std::string cur;
+    for (char c : chunk) {
+        if (c == '\n') { if (!cur.empty()) lines.push_back(cur); cur.clear(); }
+        else if (c != '\r') cur.push_back(c);
+    }
+    if (!cur.empty()) lines.push_back(cur);
+    // When we seeked into the middle of the file the first line is a fragment — drop it.
+    if (start > 0 && !lines.empty()) lines.erase(lines.begin());
+    if (static_cast<int>(lines.size()) > maxLines)
+        lines.erase(lines.begin(), lines.end() - static_cast<std::ptrdiff_t>(maxLines));
+    return lines;
+}
+
 void App::renderShutdownScreen()
 {
     using namespace ui::material;
@@ -5974,6 +6007,10 @@ void App::renderShutdownScreen()
     // -------------------------------------------------------------------
     if (daemon_controller_) {
         auto lines = daemon_controller_->recentLines(8);
+        // External daemon (attached, not spawned) has no captured stdout — tail its debug.log directly
+        // so the user can still watch the node flush the block index and exit.
+        if (lines.empty())
+            lines = tailDaemonDebugLog(8);
         if (!lines.empty()) {
             float panelW = vp_size.x * shutElem("panel-width-fraction", 0.70f);
             float panelX = cx - panelW * 0.5f;