feat(material): promote blur-overlay modal primitives (Phase 0a)

First step toward unifying all app modals on the Manage-Portfolio visual style.
Add, as shared material:: helpers (additive — no caller yet, no visible change):
- blur-overlay open refcount + 1-frame latch (Push/Pop/AnyBlurOverlayActive[LastFrame],
  LatchBlurOverlayActive) so App::render's effect guard can be modal-agnostic;
- capture-frame query (IsCapturingBlurBackdrop) for scroll-fade suppression;
- RightAlignX and SegmentedControl (promoted verbatim from market_tab);
- BeginFadeScrollChild/EndFadeScrollChild in a dedicated overlay_scroll.h (kept
  out of the widely-included draw_helpers.h because effects::ScrollFadeShader's GL
  headers clash with SDL's in some TUs).
Also fix IsCurrentWindowOverlayDialog to prefix-match "##OverlayScrim" so suffixed
overlay windows are recognized by the modal-aware hover check.

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

src/ui/material/draw_helpers.h

@@ -114,7 +114,9 @@ inline bool IsCurrentWindowOverlayDialog()
 {
     ImGuiWindow* window = ImGui::GetCurrentWindow();
     for (ImGuiWindow* node = window; node; node = node->ParentWindow) {
-        if (node->Name && strcmp(node->Name, "##OverlayScrim") == 0)
+        // Prefix match so both "##OverlayScrim" and suffixed "##OverlayScrim_<id>" blur overlays
+        // (used by nested dialogs and the unified blur-overlay framework) are recognized.
+        if (node->Name && strncmp(node->Name, "##OverlayScrim", 14) == 0)
             return true;
     }
     return false;
@@ -1027,6 +1029,75 @@ inline bool DrawDialogTitleBar(const char* title, bool* p_open, ImU32 accent_col
     return closeClicked;
 }
 
+// ============================================================================
+// Blur-backdrop modal primitives
+// ============================================================================
+// Shared building blocks for the "Manage Portfolio"-style overlay (live-blur backdrop, floating
+// content, segmented section nav, edge-fade scroll). Promoted verbatim from the Market tab so every
+// modal can adopt the same look. The overlay begin/end (below) drives these.
+
+// Refcount of open blur-backdrop overlays (nesting-safe) + a 1-frame latch. App::render builds its
+// effect-suppression guard at the TOP of the frame, before dialogs dispatch, so it must read a
+// stable "was any blur overlay up last frame" signal rather than this frame's in-progress count.
+inline int&  BlurOverlayOpenCountRef()       { static int n = 0; return n; }
+inline bool& BlurOverlayActiveLastFrameRef() { static bool v = false; return v; }
+inline void  PushBlurOverlayOpen()  { ++BlurOverlayOpenCountRef(); }
+inline void  PopBlurOverlayOpen()   { if (BlurOverlayOpenCountRef() > 0) --BlurOverlayOpenCountRef(); }
+inline bool  AnyBlurOverlayActive() { return BlurOverlayOpenCountRef() > 0; }
+inline bool  AnyBlurOverlayActiveLastFrame() { return BlurOverlayActiveLastFrameRef(); }
+// Latch this frame's state for the next frame's guard. Call once at the end of App::render.
+inline void  LatchBlurOverlayActive() { BlurOverlayActiveLastFrameRef() = AnyBlurOverlayActive(); }
+
+// True during the frames a blur overlay is (re)capturing the live backdrop — the scroll-fade shader
+// is suppressed then, since the acrylic capture rebinds render state on those frames.
+inline bool& CapturingBlurBackdropRef() { static bool v = false; return v; }
+inline bool  IsCapturingBlurBackdrop() { return CapturingBlurBackdropRef(); }
+
+// Right-align the next item(s) of total width `w` within the remaining content region (cursor form).
+inline void RightAlignX(float w)
+{
+    float avail = ImGui::GetContentRegionAvail().x;
+    if (avail > w) ImGui::SetCursorPosX(ImGui::GetCursorPosX() + avail - w);
+}
+
+// Equal-width segmented control (rounded track + N cells, each a centered label + an active pill) at
+// screen-space `origin`, spanning `totalW` x `height`. Each cell is a hit-tested InvisibleButton
+// (Hand cursor on hover), disambiguated by `idBase`. Does NOT move the layout cursor. Returns the
+// clicked cell index, or -1.
+inline int SegmentedControl(ImDrawList* dl, ImVec2 origin, float totalW, float height,
+                            const char* const* labels, int count, int selected,
+                            ImFont* font, const char* idBase, float dp)
+{
+    int clicked = -1;
+    float cellW = totalW / (float)count;
+    dl->AddRectFilled(origin, ImVec2(origin.x + totalW, origin.y + height),
+                      WithAlpha(OnSurface(), 20), height * 0.5f);
+    for (int i = 0; i < count; i++) {
+        ImVec2 cMin(origin.x + i * cellW, origin.y), cMax(cMin.x + cellW, origin.y + height);
+        bool active = (selected == i);
+        bool hov = ImGui::IsMouseHoveringRect(cMin, cMax);
+        if (active)
+            dl->AddRectFilled(ImVec2(cMin.x + 2.0f * dp, cMin.y + 2.0f * dp),
+                              ImVec2(cMax.x - 2.0f * dp, cMax.y - 2.0f * dp),
+                              WithAlpha(Primary(), 210), (height - 4.0f * dp) * 0.5f);
+        ImVec2 ts = font->CalcTextSizeA(font->LegacySize, FLT_MAX, 0, labels[i]);
+        dl->AddText(font, font->LegacySize,
+                    ImVec2(cMin.x + (cellW - ts.x) * 0.5f, cMin.y + (height - ts.y) * 0.5f),
+                    active ? IM_COL32(255, 255, 255, 255) : (hov ? OnSurface() : OnSurfaceMedium()),
+                    labels[i]);
+        ImGui::PushID(i);
+        ImGui::SetCursorScreenPos(cMin);
+        if (ImGui::InvisibleButton(idBase, ImVec2(cellW, height))) clicked = i;
+        if (ImGui::IsItemHovered()) ImGui::SetMouseCursor(ImGuiMouseCursor_Hand);
+        ImGui::PopID();
+    }
+    return clicked;
+}
+
+// The edge-fade scroll child (BeginFadeScrollChild/EndFadeScrollChild) depends on
+// effects::ScrollFadeShader, whose GL/DX headers must not be pulled into this widely-included base
+// header — it lives in material/overlay_scroll.h, included only by modal implementations.
+
 // ============================================================================
 // Fullscreen Overlay Dialog
 // ============================================================================

src/ui/material/overlay_scroll.h

@@ -0,0 +1,68 @@
+// DragonX Wallet - ImGui Edition
+// Copyright 2024-2026 The Hush Developers
+// Released under the GPLv3
+
+#pragma once
+
+// Edge-fade scroll region for the blur-backdrop modals (smooth scroll + Settings-tab edge fade +
+// a thicker, inset, rounded scrollbar). Split out of draw_helpers.h because it depends on
+// effects::ScrollFadeShader, whose GL/DX headers must not be pulled into the widely-included base
+// header (they clash with SDL's GL headers in some TUs). Include this only from modal .cpp files.
+
+#include "draw_helpers.h"                    // IsCapturingBlurBackdrop, ApplySmoothScroll
+#include "../effects/scroll_fade_shader.h"
+#include "../effects/low_spec.h"
+#include "imgui.h"
+#include <algorithm>
+#include <string>
+
+namespace dragonx {
+namespace ui {
+namespace material {
+
+// Scroll region with smooth scrolling + edge fade + a thicker, inset, rounded scrollbar. Uses a
+// bordered/rounded OUTER frame whose padding insets the scrollbar, holding an INNER scrolling child.
+// `fade` must persist across frames (one instance per scroll region); `pad` is the inner content
+// inset. Returns the inner draw list; pair with EndFadeScrollChild().
+inline ImDrawList* BeginFadeScrollChild(const char* id, effects::ScrollFadeShader& fade,
+                                        const ImVec2& pad, float dp)
+{
+    ImGui::PushStyleVar(ImGuiStyleVar_ChildRounding, 6.0f * dp);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(6.0f * dp, 6.0f * dp));
+    ImGui::BeginChild(id, ImVec2(0, std::max(120.0f * dp, ImGui::GetContentRegionAvail().y)), true,
+                      ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse);
+    ImGui::PopStyleVar(2);  // ChildRounding + outer WindowPadding (captured by the outer child)
+    ImGui::PushStyleVar(ImGuiStyleVar_ScrollbarSize, 11.0f * dp);
+    ImGui::PushStyleVar(ImGuiStyleVar_ScrollbarRounding, 5.5f * dp);
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, pad);
+    std::string innerId = std::string(id) + "_i";
+    ImGui::BeginChild(innerId.c_str(), ImVec2(0, 0), false, ImGuiWindowFlags_NoScrollWithMouse);
+    ImGui::PopStyleVar();   // inner WindowPadding — captured by this child; don't cascade to tooltips
+    ApplySmoothScroll();
+    ImDrawList* dl = ImGui::GetWindowDrawList();
+    const float fadeH = 22.0f * dp;
+    if (!effects::isLowSpecMode() && !IsCapturingBlurBackdrop() && fade.init()) {
+        ImVec2 cMin = ImGui::GetWindowPos();
+        ImVec2 cMax(cMin.x + ImGui::GetWindowSize().x, cMin.y + ImGui::GetWindowSize().y);
+        float sY = ImGui::GetScrollY(), sMax = ImGui::GetScrollMaxY();
+        fade.fadeTopY       = cMin.y;
+        fade.fadeBottomY    = cMax.y;
+        fade.fadeZoneTop    = (sY > 1.0f) ? fadeH : 0.0f;
+        fade.fadeZoneBottom = (sMax > 0.0f && sY < sMax - 1.0f) ? fadeH : 0.0f;
+        fade.addBind(dl);
+    }
+    return dl;
+}
+
+inline void EndFadeScrollChild(effects::ScrollFadeShader& fade, ImDrawList* dl)
+{
+    if (!effects::isLowSpecMode() && !IsCapturingBlurBackdrop() && fade.ready)
+        effects::ScrollFadeShader::addUnbind(dl);
+    ImGui::EndChild();       // inner
+    ImGui::PopStyleVar(2);   // ScrollbarSize + ScrollbarRounding
+    ImGui::EndChild();       // outer
+}
+
+} // namespace material
+} // namespace ui
+} // namespace dragonx