fix(ui): apply the saved appearance settings at startup

Low-spec mode, theme effects, blur, UI and noise opacity and the
console scanline reached the live effects state only once the Settings
page or the first-run wizard was opened. "Effects off" and low-spec
therefore reverted at every launch, and the animated defaults kept the
main loop busy (91% of a core on an idle Lite wallet whose effects were
saved off).

- App::applyVisualSettings(): one low-spec-aware path from the saved
  prefs to the effects state, used at startup (after the skin, since
  setActiveSkin reloads the effect config), by the low-spec hotkey, the
  wizard and the Settings page.
- Low-spec stays a runtime-only override. The Settings page shows the
  overrides but persists the real prefs from its snapshot, and opening
  it under low-spec no longer turns theme effects and blur back on.
  Unticking a low-spec in the wizard that was loaded rather than ticked
  there now restores the saved prefs.
- Theme effects on/off always pairs with reduced transparency (the
  rainbow, shimmer and glare layers), as at startup and in the hotkeys.
- kAcrylicMaxBlur moves to imgui_acrylic.h, so startup clamps blur
  values saved in the old 0-4 range the way the slider does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/app_wizard.cpp

@@ -357,13 +357,9 @@ void App::renderFirstRunWizard() {
                 if (lang.first == wiz_cur_lang) { wiz_language_index = idx; break; }
                 idx++;
             }
-            // Apply loaded settings to runtime so visuals match slider values
-            ui::effects::setLowSpecMode(wiz_low_spec);
-            ui::effects::ImGuiAcrylic::ApplyBlurAmount(wiz_blur_amount);
-            ui::effects::ImGuiAcrylic::SetUIOpacity(wiz_ui_opacity);
-            ui::effects::ThemeEffects::instance().setEnabled(wiz_theme_effects);
-            ui::effects::ThemeEffects::instance().setReducedTransparency(!wiz_theme_effects);
-            ui::ConsoleTab::s_scanline_enabled = wiz_scanline;
+            // Apply the loaded settings to the runtime (same low-spec-aware path as startup) so the
+            // visuals match the slider values
+            applyVisualSettings();
             wiz_appearance_init = true;
         }
 
@@ -538,6 +534,9 @@ void App::renderFirstRunWizard() {
             settings_->setScanlineEnabled(wiz_scanline);
             settings_->setLowSpecMode(wiz_low_spec);
             settings_->save();
+            // Make the runtime match what was just saved, both ways: unticking a low-spec that was
+            // loaded rather than ticked here has no snapshot, so the branch above pushes nothing.
+            applyVisualSettings();
         }
         ImGui::PopStyleVar();
         ImGui::SameLine();