feat(ux): copy-to-clipboard confirmations + scale wizard buttons for HiDPI

Feedback-convention + HiDPI cleanup (from the audit's living-hygiene threads):
- Copy actions that were silent now toast a confirmation: transaction
  address/txid (context menu, click-to-copy, detail buttons), peer and banned-
  peer addresses, the Settings data-dir copy, the chat message "Copy", and the
  key-export result copy.
- The first-run wizard's Skip/Back buttons used raw ImVec2(120/80,0) widths that
  rendered tiny at HiDPI; they now multiply by ui::Layout::dpiScale().

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

src/app.cpp

@@ -3590,7 +3590,7 @@ void App::renderLiteFirstRunPrompt()
             ImGui::SameLine();
             if (ui::material::TactileButton(TR("appx_copy"), ImVec2(80 * dp, 0))) copySecretToClipboard(seed);
             ImGui::SameLine();
-            if (ui::material::TactileButton(skipConfirm ? TR("appx_skip_anyway") : TR("appx_skip"), ImVec2(120, 0))) {
+            if (ui::material::TactileButton(skipConfirm ? TR("appx_skip_anyway") : TR("appx_skip"), ImVec2(120.0f * ui::Layout::dpiScale(), 0))) {
                 if (!skipConfirm) {
                     skipConfirm = true;  // require a second, deliberate click
                 } else {
@@ -3653,9 +3653,9 @@ void App::renderLiteFirstRunPrompt()
             }
             if (!verified) ImGui::EndDisabled();
             ImGui::SameLine();
-            if (ui::material::TactileButton(TR("appx_back"), ImVec2(80, 0))) { skipConfirm = false; step = 1; }
+            if (ui::material::TactileButton(TR("appx_back"), ImVec2(80.0f * ui::Layout::dpiScale(), 0))) { skipConfirm = false; step = 1; }
             ImGui::SameLine();
-            if (ui::material::TactileButton(skipConfirm ? TR("appx_skip_anyway") : TR("appx_skip"), ImVec2(120, 0))) {
+            if (ui::material::TactileButton(skipConfirm ? TR("appx_skip_anyway") : TR("appx_skip"), ImVec2(120.0f * ui::Layout::dpiScale(), 0))) {
                 if (!skipConfirm) {
                     skipConfirm = true;  // require a second, deliberate click
                 } else {
@@ -3752,7 +3752,7 @@ void App::renderLiteFirstRunPrompt()
                 }
                 ImGui::EndDisabled();
                 ImGui::SameLine();
-                if (ui::material::TactileButton(TR("appx_back"), ImVec2(80, 0))) {
+                if (ui::material::TactileButton(TR("appx_back"), ImVec2(80.0f * ui::Layout::dpiScale(), 0))) {
                     sodium_memzero(restoreSeed, sizeof(restoreSeed));
                     restoreErr.clear();
                     step = 0;
@@ -4324,8 +4324,10 @@ void App::renderExportKeyDialog()
         ImGui::TextColored(ImGui::ColorConvertU32ToFloat4(m::OnSurfaceMedium()), "%s", TR("key_export_private_key"));
         ImGui::InputTextMultiline("##exportresult", export_result_, sizeof(export_result_),
                                   ImVec2(-1, 60.0f * dp), ImGuiInputTextFlags_ReadOnly);
-        if (m::TactileButton(TR("copy")))
+        if (m::TactileButton(TR("copy"))) {
             ImGui::SetClipboardText(export_result_);
+            ui::Notifications::instance().info(TR("copied_to_clipboard"));
+        }
     } else if (export_error_) {
         ImGui::Spacing();
         ImGui::PushTextWrapPos(0.0f);

src/ui/pages/settings_page.cpp

@@ -2331,8 +2331,10 @@ void RenderSettingsPage(App* app) {
                         cs.hoverBg = material::WithAlpha(OnSurface(), 30);
                         cs.tooltip = TR("copy");
                         const float ih = ImGui::GetFrameHeight();
-                        if (material::IconButton("##copydir", ICON_MD_CONTENT_COPY, Type().iconSmall(), ImVec2(ih, ih), cs))
+                        if (material::IconButton("##copydir", ICON_MD_CONTENT_COPY, Type().iconSmall(), ImVec2(ih, ih), cs)) {
                             ImGui::SetClipboardText(dirPath.c_str());
+                            Notifications::instance().info(TR("copied_to_clipboard"));
+                        }
                     }
 
                     // Row 2: Wallet size — label left, value RIGHT-aligned.

src/ui/windows/chat_tab.cpp

@@ -1738,7 +1738,10 @@ void RenderChatTab(App* app)
                         }
                     }
                     if (ImGui::BeginPopup("##msgmenu")) {
-                        if (ImGui::MenuItem(TR("copy"))) ImGui::SetClipboardText(m.body.c_str());
+                        if (ImGui::MenuItem(TR("copy"))) {
+                            ImGui::SetClipboardText(m.body.c_str());
+                            Notifications::instance().success(TR("copied"));
+                        }
                         ImGui::EndPopup();
                     } else if (s_msgmenu_index == static_cast<int>(mi)) {
                         s_msgmenu_index = -1;   // popup closed

src/ui/windows/peers_tab.cpp

@@ -776,9 +776,11 @@ void RenderPeersTab(App* app)
                         ImGui::Separator();
                         if (ImGui::MenuItem(TR("copy_address"))) {
                             ImGui::SetClipboardText(peer.addr.c_str());
+                            ui::Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         if (ImGui::MenuItem(TR("peers_copy_ip"))) {
                             ImGui::SetClipboardText(ExtractIP(peer.addr).c_str());
+                            ui::Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         ImGui::Separator();
                         if (ImGui::MenuItem(TR("peers_ban_24h"))) {
@@ -892,6 +894,7 @@ void RenderPeersTab(App* app)
                     if (effects::ImGuiAcrylic::BeginAcrylicContextItem(nullptr, 0, acrylicTheme2.menu)) {
                         if (ImGui::MenuItem(TR("copy_address"))) {
                             ImGui::SetClipboardText(banned.address.c_str());
+                            ui::Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         if (ImGui::MenuItem(TR("peers_unban"))) {
                             app->unbanPeer(banned.address);

src/ui/windows/transactions_tab.cpp

@@ -3,6 +3,7 @@
 // Released under the GPLv3
 
 #include "transactions_tab.h"
+#include "../notifications.h"
 #include "transaction_details_dialog.h"
 #include "export_transactions_dialog.h"
 #include "transactions_tab_helpers.h"
@@ -905,9 +906,11 @@ void RenderTransactionsTab(App* app)
                     if (effects::ImGuiAcrylic::BeginAcrylicContextItem("TxContext", 0, acrylicTheme.menu)) {
                         if (ImGui::MenuItem(TR("copy_address")) && !tx.address.empty()) {
                             ImGui::SetClipboardText(tx.address.c_str());
+                            Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         if (ImGui::MenuItem(TR("copy_txid"))) {
                             ImGui::SetClipboardText(tx.txid.c_str());
+                            Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         ImGui::Separator();
                         if (ImGui::MenuItem(TR("view_on_explorer"))) {
@@ -950,7 +953,10 @@ void RenderTransactionsTab(App* app)
                         Type().textColored(TypeStyle::Overline, OnSurfaceMedium(), TR("transaction_id"));
                         ImGui::TextWrapped("%s", tx.txid.c_str());
                         if (ImGui::IsItemHovered()) ImGui::SetMouseCursor(ImGuiMouseCursor_Hand);
-                        if (ImGui::IsItemClicked()) ImGui::SetClipboardText(tx.txid.c_str());
+                        if (ImGui::IsItemClicked()) {
+                            ImGui::SetClipboardText(tx.txid.c_str());
+                            Notifications::instance().info(TR("copied_to_clipboard"));
+                        }
                         ImGui::Dummy(ImVec2(0, Layout::spacingSm()));
 
                         // Memo
@@ -972,10 +978,12 @@ void RenderTransactionsTab(App* app)
                         ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, schema::UI().drawElement("tabs.transactions", "detail-btn-rounding").size);
                         if (TactileSmallButton(TrId("copy_txid", "detail").c_str(), S.resolveFont("button"))) {
                             ImGui::SetClipboardText(tx.txid.c_str());
+                            Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         ImGui::SameLine();
                         if (!tx.address.empty() && TactileSmallButton(TrId("copy_address", "detail").c_str(), S.resolveFont("button"))) {
                             ImGui::SetClipboardText(tx.address.c_str());
+                            Notifications::instance().info(TR("copied_to_clipboard"));
                         }
                         ImGui::SameLine();
                         if (TactileSmallButton(TrId("explorer", "detail").c_str(), S.resolveFont("button"))) {