feat(market): migrate portfolio modal onto the shared blur-overlay framework (Phase 1)

Dogfood the Phase 0 framework: RenderPortfolioEditor now opens via
material::BeginOverlayDialog(BlurFloat) + EndOverlayDialog instead of its own
inline overlay scaffold, and uses the promoted material:: SegmentedControl /
RightAlignX / BeginFadeScrollChild helpers (overlay_scroll.h). Delete the
portfolio's inline backdrop/capture-once state machine + its PfEditState capture
statics + the four local helper copies. App::render's ModalRenderGuard is now
driven by the modal-agnostic AnyBlurOverlayActiveLastFrame() (timing-equivalent),
and LatchBlurOverlayActive() at frame end handles the acrylic re-capture on close.

Framework tweak: floating cards pop the card WindowPadding after BeginChild (so
nested children don't inherit it) and center button labels, keeping the net
style-var count at 2 so EndOverlayDialog is unchanged and GlassCard stays
byte-identical. RenderPortfolioEditor: 357 -> 282 lines. Needs GUI verification
that the portfolio modal is visually/behaviourally unchanged.

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

src/ui/material/draw_helpers.h

@@ -1269,6 +1269,13 @@ inline bool BeginOverlayDialog(const OverlayDialogSpec& spec)
     bool childVisible = ImGui::BeginChild(childId.c_str(),
         ImVec2(cardWidth, fixedHeight ? (cardBottomY - cardY) : 0.0f),
         cflags, ImGuiWindowFlags_NoScrollbar);
+    // Floating (portfolio-style) cards: the padding applies to this content child only, so pop it
+    // now (nested children mustn't inherit it), and center button labels. Net style-var count stays
+    // at 2 (ChildRounding + ButtonTextAlign) so EndOverlayDialog's PopStyleVar(2) is unchanged.
+    if (floating) {
+        ImGui::PopStyleVar();  // WindowPadding
+        ImGui::PushStyleVar(ImGuiStyleVar_ButtonTextAlign, ImVec2(0.5f, 0.5f));
+    }
 
     if (childVisible && spec.title) {
         if (plainHd) {