perf: optimize Divina animated playback

[everpcpc]

Problem

Divina animated images were prone to stutter because frame metadata lookup, frame decode work, and extra static-layer processing were still happening on the main playback path.

Approach

Move animated frame decoding behind a dedicated frame store so metadata is cached once, frames are downsampled for the display target, and the main thread only advances timing and swaps layer contents. Use poster frames during preload, and disable the static image layer, sepia overlay, and Live Text analysis while animation playback is active.

Scope

• cache animated frame durations and poster frames
• decode and prefetch frames off the main thread with bounded buffering
• preload animated pages with poster frames instead of full static image decode
• reduce overlay and analysis work during active animation playback
• bump build number to 353

Validation

• make format
• make build