Added #

• Pinned mode with PinnedScrollSection for viewport-sticky scrubbing.
• SliverScrollSequence for CustomScrollView integration.
• ScrollSequenceController for programmatic jump-to-frame/progress, preloading, and cache management.
• NetworkFrameLoader for HTTP frame loading with disk caching (dart:io HttpClient).
• SpriteSheetLoader with multi-sheet grid extraction and lazy-loaded sheet caching.
• Three PreloadStrategy implementations: eager, chunked (sliding window), progressive (keyframes first).
• SnapConfig with three constructors: explicit points, everyNFrames, scenes.
• SnapController with velocity-based momentum detection for fast snap triggering.
• Lifecycle callbacks: onEnter, onLeave, onEnterBack, onLeaveBack via ViewportObserver state machine.
• Horizontal scrolling via scrollDirection: Axis.horizontal parameter.
• builder parameter for reactive overlay widgets.
• loadingBuilder with normalized 0.0-1.0 progress reporting.
• Strategy-driven cache sizing (eager keeps all frames resident).
• Direction-aware preloading for chunked and progressive strategies.
• Example app with 6 demos: basic, pinned, multi-sequence, snap, lifecycle, horizontal.

Changed #

• Ticker-based frame interpolation with configurable lerpFactor and curve.
• LRU cache uses deduplication via in-flight load tracking (Set + Completer).
• Snap controller uses raw progress (not lerped) to prevent overshoot.
• Non-pinned mode uses ScrollPosition listener instead of NotificationListener.

Fixed #

• Eager strategy cache eviction when frameCount > maxCacheSize.
• Snap overshoot caused by lerp lag in progress delta calculation.
• Non-pinned mode frame updates (NotificationListener architecture bug).
• Frame centering in pinned mode via Center wrapper.

Added #

• ScrollSequence widget for scroll-driven image sequence animation.
• FrameController for progress-to-frame-index mapping with ChangeNotifier.
• FrameCacheManager with LRU eviction and proper ui.Image disposal.
• AssetFrameLoader for loading frames from Flutter asset bundles.
• FramePathResolver for {index} pattern-based path resolution.
• FrameDisplay widget with gapless playback via nearest-frame fallback.
• ScrollProgressTracker for viewport-relative scroll progress calculation.
• FrameInfo and ScrollSequenceConfig immutable data models.