Delete declarations that Periphery reports unused on every platform that
compiles them (iOS, macOS, tvOS), including nine views used only by their
own previews. Platform-gated code still used on another platform, device-
only MPV render paths, migration models, CloudKit record names, App
Intents metadata and unused parameters are kept.
The handler picked the first scroll view under the nearest ancestor,
which in the corner layout is one of the side column pages, so pulling
down on the expanded below-video panel never collapsed it. Match the
background view's window frame instead and re-attach when the match
changes.
Overdragging the side column's resize grabber past its minimum width now
slides the column off the trailing edge (the video grows with it), and a
swipe in from the trailing screen edge brings it back following the
finger. The seek pan skips that edge strip while the column is
collapsed. Showing the panel again restores every region hidden by its
own drag handle.
Swiping the below-video panel back up right after hiding it showed the
video clipped to a short centered box that sprang back to full size.
The hide flipped to the hidden layout in a `.logicallyComplete`
completion while the slide spring was still registered on the SwiftUI
host of the mpv render view; a reveal drag interrupting it made the
release spring start from a bogus shrunken rect. All slide-off
completions now wait for `.removed` and bail if a new drag took over.
The visibility-keyed `.animation` modifiers key on a toggle generation
bumped only by the animated show/hide paths, so drag flips never start
the toggle easing. The partnerless `matchedGeometryEffect` on the
widescreen video frame is dropped.
Left/right on the Siri Remote now seek instead of revealing controls,
reusing the iOS tap-seek accumulation handler and feedback overlay so
rapid presses compound into a single "+30s" / "-20s" jump. Up/down
still show controls.
Extract shared TimeInterval.formattedAsTimestamp replacing 8 identical
formatTime/formattedTime implementations across player views. Remove
unused currentTime parameter from GestureSeekPreviewView. Consolidate
duplicated geometry math in MacOSControlBar into seekPreviewPosition().
Extract chapter title from inside the storyboard preview into a
standalone ChapterCapsuleView with its own glass capsule background.
The capsule follows the seek position horizontally but independently
clamps to screen edges using alignmentGuide, allowing it to be wider
than the storyboard thumbnail without going offscreen.
