refactor(ui): trim header trigger labels and fix dropdown anchoring

OpenInAppButton and ProjectActionsButton now render icon-only triggers in the header instead of icon + text. Padding is tightened accordingly and the now-unused selectedButtonLabel / formatActionButtonLabel helpers are gone.

With narrower triggers the previous center-aligned dropdown with translate -30px started overflowing the viewport on the left edge for ProjectActions. Switched ProjectActions dropdown to align="start" and OpenInApp dropdown to align="end" (matching their positions in the header) and removed the manual translate offset.

Also fixed a long-standing inconsistency where clicking an already-running action in the ProjectActions dropdown re-ran it instead of stopping; the non-compact branch was missing toggleStopIfRunning=true that the compact branch already passed.

MiniChat header now uses bg-sidebar to match the main desktop header palette.

packages/ui/src/components/desktop/OpenInAppButton.tsx

@@ -142,8 +142,9 @@ export const OpenInAppButton = ({ directory, className }: OpenInAppButtonProps)
         type="button"
         onClick={() => void handleOpen(selectedApp)}
         className={cn(
-          'inline-flex h-full items-center gap-2 px-3 typography-ui-label font-medium',
-          'text-foreground hover:bg-interactive-hover transition-colors'
+          'inline-flex h-full items-center px-2.5 typography-ui-label font-medium',
+          'text-foreground hover:bg-interactive-hover transition-colors',
+          isScanning && 'animate-pulse'
         )}
         aria-label={t('openInApp.actions.openInAria', { app: selectedApp.label })}
       >
@@ -152,9 +153,6 @@ export const OpenInAppButton = ({ directory, className }: OpenInAppButtonProps)
           iconDataUrl={selectedApp.iconDataUrl}
           fallbackIconDataUrl={selectedApp.fallbackIconDataUrl}
         />
-        <span className={cn('header-open-label', isScanning ? 'animate-pulse text-muted-foreground' : undefined)}>
-          {t('openInApp.actions.open')}
-        </span>
       </button>
       <DropdownMenu>
         <DropdownMenuTrigger asChild>
@@ -171,9 +169,8 @@ export const OpenInAppButton = ({ directory, className }: OpenInAppButtonProps)
           </button>
         </DropdownMenuTrigger>
         <DropdownMenuContent
-          align="center"
+          align="end"
           className="w-56 max-h-[70vh] overflow-y-auto"
-          style={{ translate: '-30px 0' }}
         >
           <DropdownMenuItem className="flex items-center gap-2" onClick={() => void handleCopyPath()}>
             <Icon name="file-copy" className="h-4 w-4" />