UI overhaul: minimal library, swipeable Now Playing, speed on every track

[EnesYilmazcode]

Redesign of every screen after a full audit.

• Library: title-only rows, one options menu (import, backup, restore, sort, favorites filter), no header clutter
• Now Playing: swipe down to close, swipe up on the mini player to open, artwork backdrop, custom scrubber
• Numbered series tracks get a number tile as artwork
• Playback speed lives in the Now Playing menu and applies to every track, saved across launches
• Tab bar is Library, Search, Playlists; podcast code stays but is off the tab bar
• Shared action sheet with drag to dismiss; holding a row no longer taps the sheet on release
• iOS polish: safe areas, press states, translucent dock, no tap highlight or callouts

Checked with vite build, test-features, test-import, test-series and iPhone 13 / SE screenshots.