merge #254: mobile explain unavailable sidebar and prevent overflow

# Conflicts:
#	README.md
#	README_EN.md
#	dsh.plugin.json
#	package.json
#	src/client/service.ts

src/client/Sidebar.tsx

@@ -1030,18 +1030,20 @@ export function Sidebar(props: { ctx: Context; store: SidebarStore }) {
   }, [ctx, sessionId, cwd])
 
   if (state === undefined || sessionId === undefined) {
+    // Keep the unavailable controls focusable: touch users have no hover, so
+    // focus is the only way the existing Tooltip can explain what is missing.
     return (
       <div data-dsh-panel-host {...osFileDragShield}>
         <div className={css.toggleCluster} data-dsh-toggle-cluster>
           {!narrow && (
             <Tooltip label={t('noSession')} side="bottom" delayMs={500}>
-              <button type="button" className={css.toggleButton} disabled aria-label={t('noSession')}>
+              <button type="button" className={css.toggleButton} aria-disabled="true" aria-label={t('noSession')}>
                 <IconPanelBottomOutline16 />
               </button>
             </Tooltip>
           )}
           <Tooltip label={t('noSession')} side="bottom" delayMs={500}>
-            <button type="button" className={css.toggleButton} disabled aria-label={t('noSession')}>
+            <button type="button" className={css.toggleButton} aria-disabled="true" aria-label={t('noSession')}>
               <IconPanelRightOutline16 />
             </button>
           </Tooltip>

src/client/sidebar.module.css

@@ -105,17 +105,19 @@
     color var(--ds-transition-duration-slow) var(--ds-ease-in-out);
 }
 
-.toggleButton:hover:not(:disabled) {
+.toggleButton:hover:not(:disabled):not([aria-disabled='true']) {
   background: var(--dsw-alias-interactive-bg-hover);
   color: var(--dsw-alias-label-primary);
 }
 
-.toggleButton:disabled {
+.toggleButton:disabled,
+.toggleButton[aria-disabled='true'] {
   opacity: 0.4;
   cursor: default;
 }
 
 .panel {
+  box-sizing: border-box;
   position: absolute;
   top: 0;
   right: 0;