fix(app): polish workspace navigation surfaces

Use mobile action sheets and long-press file menus while preserving provider context across sheet portals. Keep sidebar and file-pane glyphs on shared visual rails, avoid scrollbar layout shifts, and hide keyboard affordances where shortcuts are unavailable.

packages/app/src/components/sidebar-workspace-list.tsx

@@ -495,7 +495,7 @@ function ProjectKebabMenu({
 }) {
   const { t } = useTranslation();
   return (
-    <DropdownMenu>
+    <DropdownMenu compactMode="sheet">
       <DropdownMenuTrigger
         hitSlop={8}
         style={projectKebabStyle}
@@ -505,7 +505,7 @@ function ProjectKebabMenu({
       >
         {renderKebabTriggerIcon}
       </DropdownMenuTrigger>
-      <DropdownMenuContent align="end" width={220}>
+      <DropdownMenuContent align="end" width={220} sheetTitle={t("sidebar.project.actions.menu")}>
         <ProjectMenuItems
           surface="dropdown"
           projectViewKey={projectViewKey}
@@ -2541,6 +2541,9 @@ const styles = StyleSheet.create((theme) => ({
     alignItems: "center",
     gap: 2,
     flexShrink: 0,
+    // MoreVertical paints only around the center of its 14px SVG. Keep the 24px controls,
+    // but pull their painted edge through the unused view-box space onto the row rail.
+    marginRight: -6,
   },
   projectKebabButton: {
     width: 24,