fix(desktop): allow selecting slash output and shell logs in thread (#49063)

System messages (/debug, /status, etc.) were not in the desktop app's
text-selection allowlist, so log output in the thread could not be copied.

apps/desktop/src/components/assistant-ui/thread.tsx

@@ -859,7 +859,10 @@ const ProcessNotificationNote: FC<{ text: string }> = ({ text }) => {
           <summary className="cursor-pointer select-none text-muted-foreground/45 hover:text-muted-foreground/70">
             output
           </summary>
-          <pre className="mt-0.5 max-h-48 overflow-auto whitespace-pre-wrap font-mono text-[0.625rem] leading-4 text-muted-foreground/55">
+          <pre
+            className="mt-0.5 max-h-48 overflow-auto whitespace-pre-wrap font-mono text-[0.625rem] leading-4 text-muted-foreground/55"
+            data-selectable-text="true"
+          >
             {detail}
           </pre>
         </details>

apps/desktop/src/components/chat/terminal-output.tsx

@@ -41,7 +41,11 @@ export function TerminalOutput({ className, text }: TerminalOutputProps) {
   }, [text])
 
   return (
-    <div className={cn('max-h-16 overflow-auto overscroll-contain', className)} ref={ref}>
+    <div
+      className={cn('max-h-16 overflow-auto overscroll-contain', className)}
+      data-selectable-text="true"
+      ref={ref}
+    >
       <pre className="w-max min-w-full font-mono text-[0.5625rem] leading-[0.85rem] whitespace-pre text-muted-foreground/70">
         {text}
       </pre>

apps/desktop/src/styles.css

@@ -680,6 +680,7 @@ textarea,
 [contenteditable]:not([contenteditable='false']),
 [data-slot='aui_user-message-root'],
 [data-slot='aui_assistant-message-content'],
+[data-slot='aui_system-message-root'],
 [data-selectable-text='true'],
 [data-selectable-text='true'] * {
   -webkit-user-select: text;