refactor(settings): import dialog layout polish

Several layout refinements to the Import Private/Viewing Key dialog:
- Widen the dialog to 640px so the one-line warning under the heading no longer wraps.
- Vertically center DialogWarningHeader's label with the (taller) warning icon
  instead of top-aligning it — a consistent fix for every warning header.
- Add a small gap between the key input's text and the flush eye toggle.
- Center + slightly enlarge the Paste / Clear buttons.
- Center the Import/Sweep + Close action buttons.
- Scan-height control: put the numeric input first with the slider below it, and
  drop the redundant "0 = rescan from the start" hint (0 is the field default; the
  transparent-key note is kept).

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

src/app.cpp

@@ -2775,8 +2775,15 @@ static void RenderScanHeightControl(char* buf, size_t bufSize, int tipHeight, bo
 
     ImGui::BeginDisabled(!enabled);
 
+    // Numeric entry first — the slider sits below it.
+    ImGui::SetNextItemWidth(availW);
+    ImGui::InputText("##importscanheight", buf, bufSize, ImGuiInputTextFlags_CharsDecimal);
+    cur = buf[0] ? std::atoi(buf) : 0;   // reflect a just-typed value in the slider below
+    if (cur < 0) cur = 0;
+
     if (tipHeight > 0) {
-        const float barW = availW;                    // slider spans the panel interior, stacked above the field
+        ImGui::Spacing();
+        const float barW = availW;                    // slider spans the panel interior, below the field
         const float barH = ImGui::GetFrameHeight();   // match the numeric field's height (already dp-scaled)
         const float barRound = barH * 0.5f;
         const float thumbR = barH * 0.5f;
@@ -2828,10 +2835,6 @@ static void RenderScanHeightControl(char* buf, size_t bufSize, int tipHeight, bo
         }
     }
 
-    // Exact numeric entry — full-width beneath the slider.
-    ImGui::SetNextItemWidth(availW);
-    ImGui::InputText("##importscanheight", buf, bufSize, ImGuiInputTextFlags_CharsDecimal);
-
     ImGui::EndDisabled();
 }
 
@@ -2845,7 +2848,7 @@ void App::renderImportKeyDialog()
     ov.title    = viewMode ? TR("import_viewkey_title") : TR("import_key_title");
     ov.p_open   = &show_import_key_;
     ov.style    = m::OverlayStyle::BlurFloat;
-    ov.cardWidth = 520.0f;
+    ov.cardWidth = 640.0f;   // wide enough that the one-line warning under the heading doesn't wrap
     ov.idSuffix  = "importkey";
     if (!m::BeginOverlayDialog(ov)) return;
 
@@ -2902,21 +2905,26 @@ void App::renderImportKeyDialog()
     // revealed) — like the send tab — so the user can verify before pasting.
     const float fieldH = ImGui::GetFrameHeight();
     const ImVec2 iconSz(fieldH, fieldH);
-    ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x - fieldH);
+    const float eyeGap = ui::Layout::spacingSm();   // breathing room between the text and the eye button
+    ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x - fieldH - eyeGap);
     ImGuiInputTextFlags flags = import_key_reveal_ ? 0 : ImGuiInputTextFlags_Password;
     ImGui::InputText("##importkey", import_key_input_, sizeof(import_key_input_), flags);
     const ImVec2 fieldMin = ImGui::GetItemRectMin();   // anchor for the paste-preview overlay
-    ImGui::SameLine(0, 0);
+    ImGui::SameLine(0, eyeGap);
     m::IconButtonStyle eyeSt;
     eyeSt.hoverBg = m::WithAlpha(m::OnSurface(), 30);
-    eyeSt.bgRounding = 4.0f * dp;   // match the input frame's corners (it sits flush at the field's edge)
+    eyeSt.bgRounding = 4.0f * dp;
     eyeSt.tooltip = TR("import_key_reveal_tip");
     if (m::IconButton("##revealkey", import_key_reveal_ ? ICON_MD_VISIBILITY_OFF : ICON_MD_VISIBILITY,
                       m::Type().iconSmall(), iconSz, eyeSt))
         import_key_reveal_ = !import_key_reveal_;
 
-    // Paste / Clear — labelled buttons.
-    const bool pasteClicked = m::TactileButton(TR("paste"));
+    // Paste / Clear — centered, slightly larger labelled buttons.
+    const float actBtnW = 104.0f * dp;
+    const float actTotal = actBtnW * 2.0f + ImGui::GetStyle().ItemSpacing.x;
+    const float actOff = (ImGui::GetContentRegionAvail().x - actTotal) * 0.5f;
+    if (actOff > 0.0f) ImGui::SetCursorPosX(ImGui::GetCursorPosX() + actOff);
+    const bool pasteClicked = m::TactileButton(TR("paste"), ImVec2(actBtnW, 0));
     const bool pasteHovered = ImGui::IsItemHovered();
     if (pasteClicked) {
         const char* clipboard = ImGui::GetClipboardText();
@@ -2928,7 +2936,7 @@ void App::renderImportKeyDialog()
         }
     }
     ImGui::SameLine();
-    if (m::TactileButton(TR("clear"))) sodium_memzero(import_key_input_, sizeof(import_key_input_));
+    if (m::TactileButton(TR("clear"), ImVec2(actBtnW, 0))) sodium_memzero(import_key_input_, sizeof(import_key_input_));
 
     // While Paste is hovered and the field is empty, preview the trimmed clipboard INSIDE the field —
     // masked with '*' unless the key is revealed — coloured by how it would classify (green ok / amber
@@ -3079,8 +3087,10 @@ void App::renderImportKeyDialog()
         RenderScanHeightControl(import_key_scan_height_, sizeof(import_key_scan_height_),
                                 tip, !transparentKey, dp, availW);
 
-        ImGui::TextColored(ImGui::ColorConvertU32ToFloat4(m::OnSurfaceDisabled()), "%s",
-                           transparentKey ? TR("import_scan_transparent") : TR("import_scan_hint"));
+        // Only note why the control is inert for a transparent key; the generic "0 = rescan from the
+        // start" hint was dropped as self-evident (0 is the field's default).
+        if (transparentKey)
+            ImGui::TextColored(ImGui::ColorConvertU32ToFloat4(m::OnSurfaceDisabled()), "%s", TR("import_scan_transparent"));
 
         ImGui::Unindent(padX);
         ImGui::Dummy(ImVec2(0, padY));
@@ -3150,6 +3160,10 @@ void App::renderImportKeyDialog()
     // Sweep needs a spending key AND a destination (a picked address when not using a fresh one).
     const bool destReady = !sweepMode || sweep_dest_mode_ == 0 || sweep_dest_pick_[0] != '\0';
     const bool canAct = recognized && state_.connected && !running && destReady;
+    // Center the action + Close buttons in the (wider) dialog.
+    const float footTotal = btnW * 2.0f + ImGui::GetStyle().ItemSpacing.x;
+    const float footOff = (ImGui::GetContentRegionAvail().x - footTotal) * 0.5f;
+    if (footOff > 0.0f) ImGui::SetCursorPosX(ImGui::GetCursorPosX() + footOff);
     ImGui::BeginDisabled(!canAct);
     if (m::TactileButton(sweepMode ? TR("sweep_button") : TR("import_key_import"), ImVec2(btnW, 0))) {
         int startHeight = 0;   // 0 = full rescan. Shielded imports (z_importkey) honor it; transparent

src/ui/material/draw_helpers.h

@@ -1666,10 +1666,16 @@ inline void BeginOverlayDialogFooter(float totalActionWidth, bool drawSeparator
 // TextColored(label).  The label text is passed in (already translated).
 inline void DialogWarningHeader(const char* warningLabel, const ImVec4& col = WarningVec4())
 {
-    ImGui::PushFont(Type().iconLarge());
+    ImFont* iconF = Type().iconLarge();
+    const float rowTop = ImGui::GetCursorPosY();
+    const float iconH  = iconF->LegacySize;      // already dp-scaled
+    const float textH  = ImGui::GetFontSize();
+    ImGui::PushFont(iconF);
     ImGui::TextColored(col, ICON_MD_WARNING);
     ImGui::PopFont();
     ImGui::SameLine();
+    // Vertically center the label with the taller warning glyph (stays within the icon's row height).
+    if (iconH > textH) ImGui::SetCursorPosY(rowTop + (iconH - textH) * 0.5f);
     ImGui::TextColored(col, "%s", warningLabel);
 }