feat: Full UI internationalization, pool hashrate stats, and layout caching

- Replace all hardcoded English strings with TR() translation keys across
  every tab, dialog, and component (~20 UI files)
- Expand all 8 language files (de, es, fr, ja, ko, pt, ru, zh) with
  complete translations (~37k lines added)
- Improve i18n loader with exe-relative path fallback and English base
  fallback for missing keys
- Add pool-side hashrate polling via pool stats API in xmrig_manager
- Introduce Layout::beginFrame() per-frame caching and refresh balance
  layout config only on schema generation change
- Offload daemon output parsing to worker thread
- Add CJK subset fallback font for Chinese/Japanese/Korean glyphs

src/ui/effects/theme_effects.h

@@ -105,6 +105,12 @@ public:
     bool hasSandstorm()        const { return enabled_ && sandstorm_.enabled; }
     bool hasViewportOverlay()  const { return enabled_ && (viewport_overlay_.colorWashEnabled || viewport_overlay_.vignetteEnabled); }
 
+    /// True when any per-panel visual effect is active (rainbow, shimmer, specular, edge, ember, gradient)
+    bool hasAnyPanelEffect() const {
+        return hasRainbowBorder() || hasShimmer() || hasSpecularGlare()
+            || hasEdgeTrace() || hasEmberRise() || hasGradientBorder();
+    }
+
     /// True when any time-dependent effect is active and needs continuous redraws
     bool hasActiveAnimation() const {
         if (!enabled_) return false;