feat(contacts): animated avatars (GIF/WebP) with a Settings toggle

Animate contact avatars end to end:

- texture_loader gains LoadAnimatedRGBA: decodes an image into a downscaled
  RGBA frame sequence + per-frame durations — animated GIF via stb
  (stbi_load_gif_from_memory) and animated WebP via libwebp's WebPAnimDecoder;
  stills (and APNG, which stb reads as one image) return a single frame. Frames
  are box-downscaled (smaller cap for animations) to bound VRAM, capped at 300.
- The contacts avatar cache now holds a frame sequence; currentAvatarFrame()
  advances animated avatars by the ImGui clock and is used everywhere avatars
  draw (list, cards, table, grid, preview). When a live animated frame is drawn
  it flags the render loop (ConsumeContactsAvatarAnimation, clear-on-read) so
  main.cpp keeps producing frames while animation plays and idles when it stops
  or the contacts view is hidden.
- New animate_avatars setting (default on) + a Settings appearance toggle
  ("Animate avatars"); off shows the first frame only. currentAvatarFrame
  honors it. +i18n (8 langs, CJK subset rebuilt for 帧/播/첫).

Verified: a 3-frame GIF and a 3-frame animated WebP both decode to 3 frames
with correct 120ms delays through the exact libwebp/stb calls used here.

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

src/main.cpp

@@ -9,6 +9,7 @@
 #include "ui/schema/ui_schema.h"
 #include "ui/effects/low_spec.h"
 #include "ui/notifications.h"
+#include "ui/windows/contacts_tab.h"
 #include "ui/theme.h"
 #include "ui/material/color_theme.h"
 #include "ui/material/typography.h"
@@ -1970,7 +1971,8 @@ int main(int argc, char* argv[])
                           || app.isTransactionRefreshInProgress()
                           || dragonx::ui::effects::ThemeEffects::instance().hasActiveAnimation()
                           || dragonx::ui::Notifications::instance().hasActive()
-                          || dragonx::ui::material::SmoothScrollAnimating();
+                          || dragonx::ui::material::SmoothScrollAnimating()
+                          || dragonx::ui::ConsumeContactsAvatarAnimation();
             // If nothing is happening, allow the next iteration to idle
             needsRedraw = uiActive || animating;
         }