The Material theme now draws its main surfaces with rounded Material
Symbols: navigation, player, mini player, queue, settings, sheets,
dialogs and shared controls. AppIcon maps legacy Icons to their symbol
and keeps outlined glyphs unfilled. Mornye keeps its original icons.
Icon buttons, text and filled buttons, dialog actions, sliders, the setup
FAB and indeterminate spinners use the Material 3 Expressive components.
Each wrapper falls back to the standard Flutter widget for Mornye, reduced
motion and custom sizing, so existing layouts and hit areas stay intact.
Single homes for logic that was copy-pasted across screens: the settings
collapsing header, album detail header (online screen's design as the
reference), selection pill button + bottom-bar chrome, disc separator
chip, error card, cover URL upgrade, byte/clock formatting, duration
extraction, UnifiedLibraryItem (moved out of the queue_tab library so
other screens can import it), and the batch convert/ReplayGain engine
keyed on it.