Add a plus icon to indicate creating a new note

Update the notes composer component to include a Plus icon next to the "Take a note..." placeholder, visually indicating the action to create a new note.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 77cfe984-2c65-4152-bb7a-0df28274fe66
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: 01f3a5db-a2fa-45cb-9733-81a92ebf3216
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/c3c252e4-c83d-40ca-9fff-99a3ea60701e/77cfe984-2c65-4152-bb7a-0df28274fe66/mkNwf1z
Replit-Helium-Checkpoint-Created: true

artifacts/tx-os/src/pages/notes.tsx

@@ -2772,10 +2772,17 @@ function Composer({
       ) : (
         <button
           onClick={() => setOpen(true)}
-          className="w-full text-start text-muted-foreground py-1 px-1"
+          className="w-full flex items-center gap-2 text-start text-muted-foreground py-1 px-1"
           data-testid="notes-composer-open"
         >
-          {t("notes.takeNote", "Take a note...")}
+          <Plus
+            size={18}
+            aria-hidden="true"
+            className="shrink-0 text-muted-foreground"
+          />
+          <span className="truncate">
+            {t("notes.takeNote", "Take a note...")}
+          </span>
         </button>
       )}
     </div>