1.7.2

Added

• Chapters, like YouTube. NativeVideoPlayerChapter (start + title,
  optional thumbnail), set with controller.setChapters(...) or
  load(chapters: ...). NativeVideoPlayerChapters.parseText reads the
  "0:00 Intro" list from a video description, parseVtt / fromVttUrl a
  WebVTT chapters track. The controller reports currentChapter and
  currentChapterStream, and seekToNextChapter() / seekToPreviousChapter()
  skip between them. Chapters are ignored for live streams; loading another
  URL clears them.
• NativeVideoPlayerProgressBar, a seek bar for custom overlays: buffered
  range, chapter segments with small gaps, the touched segment grows, drags
  snap to a chapter start within snapDistance (8 px) with a haptic tick,
  and an animated scrub preview with the storyboard frame, chapter title and
  time. Everything is styleable (NativeVideoPlayerProgressBarStyle,
  NativeVideoPlayerScrubPreviewStyle, or a previewBuilder), showPreview
  turns the bubble off, and position / duration / onSeek overrides let
  it run without a controller (casting, audio). Storyboard images take
  storyboardHeaders or a custom image provider, are precached around the
  playing position (storyboardPrecacheLimit), and a failed load just leaves
  the frame out. NativeVideoPlayerScrubPreview is the bubble on its own;
  NativeVideoPlayerChapters.segments / snapTarget the math for a bar of
  your own.
• Chapter events: PlayerControlState.chapterChanged (with index, title,
  startMs) and chaptersChanged reach control listeners, next to
  currentChapterStream / chaptersStream and currentChapterIndex. They
  don't restart the overlay's hide timer. The progress bar adds
  onScrubChapterChanged, onSnap and onPreviewChanged (which also fires
  with showPreview: false, to draw the preview elsewhere).
• controller.holdOverlay() keeps the custom overlay visible until the
  returned callback runs, without touching lockOverlay().
  NativeVideoPlayerProgressBar holds it while the viewer scrubs, so the
  controls never hide mid-drag.
• Scrub previews fit the player: the bubble is bounded by the room above
  the bar (up to the top of the NativeVideoPlayer) and the bar's width,
  scaled down when it doesn't fit, and left out when there is no room;
  previewMaxHeight caps it. Frames keep their real aspect ratio
  (thumbnailMaxHeight bounds portrait ones), failed images are retried on
  a later scrub, and the bar's default height fits the bar (24 px).
• Bunny storyboards without an aspectRatio measure the frame height from
  each loaded sheet (StoryboardThumbnail.regionIn, gridCell; sheets are
  padded to the full 6 × 6 grid), so portrait videos show the right frame.
• The progress bar keeps the storyboard sheets around the position loaded
  (at most storyboardPrecacheLimit), so a busy image cache can't drop them
  before the first scrub; while a sheet loads the bubble shows the time only.
• StoryboardThumbnails.bunnyFromPlaylistUrl(playlistUrl, duration:), which
  keeps a signed URL's token, and headers: on StoryboardThumbnails.fromUrl.