feat(network): give the "no peers" banner an honest detail and a Restart action

The no-peers banner headline ("Connected, but no network peers") was followed
by a detail line that just repeated connection_status ("Connected"/"Peers: 0"),
reading as a contradiction, and it offered no action at the exact moment the
wallet looks synced but is silently stalled at a stale height.

- NoPeers now clears the passthrough detail; App renders a translated,
  actionable hint (node_banner_no_peers_detail) for this reason instead.
- When the embedded daemon is the node, offer a Restart button (re-triggers
  peer discovery via the -addnode seeds); an external node stays action-less
  since it is the user's own to restart.
- Update + extend the evaluator unit tests (external = no action/empty detail;
  embedded = RestartNode).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app.cpp

@@ -2705,6 +2705,13 @@ void App::renderNodeStatusBanner()
     if      (banner.action == ui::NodeBannerAction::Reconnect)   actionLabel = TR("node_banner_reconnect");
     else if (banner.action == ui::NodeBannerAction::RestartNode) actionLabel = TR("node_banner_restart");
 
+    // The NoPeers case deliberately carries no passthrough detail (connection_status is just
+    // "Connected" there, which reads as a contradiction under the "no peers" headline). Show a
+    // translated, actionable hint instead; every other reason keeps its live status/error text.
+    const std::string detailText = (banner.reason == ui::NodeBannerReason::NoPeers)
+                                       ? std::string(TR("node_banner_no_peers_detail"))
+                                       : banner.detail;
+
     const float padX = ui::Layout::spacingLg();
 
     ImGui::PushStyleColor(ImGuiCol_ChildBg, ImGui::ColorConvertU32ToFloat4(bgCol));
@@ -2741,7 +2748,7 @@ void App::renderNodeStatusBanner()
     ImGui::PopStyleColor();
 
     // Detail (dim) on the same row, clipped with an ellipsis so it can't push the button off-screen.
-    if (!banner.detail.empty()) {
+    if (!detailText.empty()) {
         ImGui::SameLine(0.0f, ui::Layout::spacingSm());
         ImGui::SetCursorPosY(txtCy);
         const float budget = winW - ImGui::GetCursorPosX() - actionReserve;
@@ -2752,7 +2759,7 @@ void App::renderNodeStatusBanner()
             static util::textfit::EllipsisFitCache s_detailFit;   // UI thread only (render path)
             ImFont* detailFont = ImGui::GetFont();
             const std::string& shown = s_detailFit.get(
-                banner.detail, budget, detailFont->FontId, ImGui::GetFontSize(),
+                detailText, budget, detailFont->FontId, ImGui::GetFontSize(),
                 detailFont->CurrentRasterizerDensity,
                 [&](const std::string& detail) {
                     const std::string prefix = "\xC2\xB7  ";            // "·  "

src/ui/node_status_banner.h

@@ -116,14 +116,20 @@ inline NodeBannerState evaluateNodeStatusBanner(const NodeBannerInputs& in) {
 
     // Connected to the daemon (RPC works) but with no peer-derived tip → the node has no peers and
     // cannot learn about new blocks; it silently stalls at a stale height while everything looks
-    // synced. Surface it as a recoverable warning (reconnect won't help, so no action button).
+    // synced. Surface it as a recoverable warning. A plain reconnect won't help, but restarting the
+    // embedded daemon re-triggers peer discovery (it re-reads the -addnode seeds), so offer that when
+    // we own the node; an external node is the user's own to restart, so no button there. The detail
+    // is left empty: here connection_status is just "Connected", which would contradict the
+    // "no peers" headline — App renders a translated, actionable hint for this reason instead.
     if (in.connected) {
         if (!in.tip_known && in.blocks > 0) {
             s.show     = true;
             s.severity = NodeBannerSeverity::Warning;
             s.reason   = NodeBannerReason::NoPeers;
-            s.action   = NodeBannerAction::None;
-            s.detail   = in.connection_status;
+            s.action   = (in.using_embedded_daemon && in.has_daemon_controller)
+                             ? NodeBannerAction::RestartNode
+                             : NodeBannerAction::None;
+            s.detail.clear();
         }
         return s;
     }

src/util/i18n.cpp

@@ -1543,6 +1543,7 @@ void I18n::loadBuiltinEnglish()
         // Persistent node-status banner (App::renderNodeStatusBanner).
         strings_["node_banner_offline_title"] = "Not connected to the DragonX node";
         strings_["node_banner_no_peers_title"] = "Connected, but no network peers — the node can't sync";
+        strings_["node_banner_no_peers_detail"] = "Check your internet connection and firewall, then restart the node to find peers.";
         strings_["node_banner_crashed_title"] = "The node stopped unexpectedly";
         strings_["node_banner_lite_open_failed"] = "Couldn't open your wallet";
         strings_["node_banner_reconnect"] = "Reconnect";

tests/test_phase4.cpp

@@ -3535,6 +3535,9 @@ void testNodeStatusBanner()
         EXPECT_TRUE(!evaluateNodeStatusBanner(in).show);
     }
     // Connected but no peer-derived tip (0 peers) once chain info is in → amber "no peers" banner.
+    // An external node (no embedded controller) gets no action button, and the detail is cleared:
+    // connection_status ("Peers: 0"/"Connected") would contradict the headline, so App renders a
+    // translated actionable hint for this reason instead.
     {
         NodeBannerInputs in;
         in.connected = true; in.tip_known = false; in.blocks = 3262059;
@@ -3544,7 +3547,17 @@ void testNodeStatusBanner()
         EXPECT_TRUE(s.severity == NodeBannerSeverity::Warning);
         EXPECT_TRUE(s.reason == NodeBannerReason::NoPeers);
         EXPECT_TRUE(s.action == NodeBannerAction::None);
-        EXPECT_EQ(s.detail, std::string("Peers: 0"));
+        EXPECT_TRUE(s.detail.empty());
+    }
+    // ...but with the embedded daemon running, offer a Restart (re-triggers peer discovery).
+    {
+        NodeBannerInputs in;
+        in.connected = true; in.tip_known = false; in.blocks = 3262059;
+        in.using_embedded_daemon = true; in.has_daemon_controller = true; in.daemon_running = true;
+        NodeBannerState s = evaluateNodeStatusBanner(in);
+        EXPECT_TRUE(s.reason == NodeBannerReason::NoPeers);
+        EXPECT_TRUE(s.action == NodeBannerAction::RestartNode);
+        EXPECT_TRUE(s.detail.empty());
     }
     // Connected, tip unknown, but no chain info yet (blocks==0) → no banner (avoid startup flicker).
     {