fix(qt): the player bar keeps the same 8 px gutter on macOS

The wider macOS gutter added for the Liquid Glass corner curve read as
excessive next to the 8 px the content pane keeps; one value on every
platform now, and the macOS-only theme token is gone with its comment.

cc

crates/qbz-qt/qml/shell/AppShell.qml

@@ -255,9 +255,8 @@ Rectangle {
     // The bottom chrome band (NowPlayingBar.qml's root): full width, flush
     // on the window's bottom edge, the same tier and paint as the HeaderBar
     // above. The bar layout inside it keeps the content pane's gutter to the
-    // window's left, right and bottom edges — wider on macOS, where the
-    // Liquid Glass corner curve ate the cover's corner (QbzTheme.npbGutterMac)
-    // — and the band sizes itself: the mode-aware layout height (Small
+    // window's left, right and bottom edges, the same on every platform —
+    // and the band sizes itself: the mode-aware layout height (Small
     // collapses to one header-tall row; New/Classic/Large keep the full
     // 112px, AppShell.slint:396) plus that gutter.
     NowPlayingBar {

crates/qbz-qt/qml/shell/NowPlayingBar.qml

@@ -29,8 +29,8 @@ Rectangle {
     QbzTheme { id: theme }
 
     /// The gutter the bar layout keeps to the window's left, right and
-    /// bottom edges: the pane's 8px, wider on macOS (QbzTheme.npbGutterMac).
-    readonly property int gutter: Qt.platform.os === "osx" ? theme.npbGutterMac : theme.npbGutter
+    /// bottom edges: the pane's 8px, the same on every platform.
+    readonly property int gutter: theme.npbGutter
     /// The layout's own height (PlayerBar.slint / PlayerBarSmall.slint).
     readonly property int layoutHeight: QbzShell.npbMode === 2 ? theme.npbSmallHeight : theme.npbLargeHeight
     implicitHeight: layoutHeight + gutter

crates/qbz-qt/qml/theme/QbzTheme.qml

@@ -422,16 +422,10 @@ QtObject {
     /// The gutter the player bar keeps to the window's left, right and
     /// bottom edges (2026-09-13): the SAME 8 px the content pane keeps
     /// inside its frame, so the bar's ends line up with the pane's and
-    /// nothing in it touches the window edge.
+    /// nothing in it touches the window edge. One value on every platform:
+    /// a wider macOS gutter for the Liquid Glass corner was tried the same
+    /// day and read as too much.
     readonly property int npbGutter: 8
-    /// macOS only: Tahoe's Liquid Glass windows round their corners far
-    /// more than before (Apple: toolbar windows take a larger radius that
-    /// "can clip content that sits close to the edge of the window";
-    /// estimates run from ~12-16 pt for titlebar-only windows to 50 px+
-    /// with a toolbar) and the cover at the bar's left end lost its corner.
-    /// Qt has no LayoutRegion to nest content into the curve, so the bar
-    /// simply keeps a wider gutter there.
-    readonly property int npbGutterMac: 16
     // Every other bar mode (New / Classic / Large) — AppShell.slint:396.
     // The Large dock's sidebar reservation subtracts this, so it must be the
     // SAME value the shell pins the bar to.