fix: allow closing last session tab and restore DevTools shortcut

Closing the sole remaining non-welcome tab now resets to welcome; enable Tauri devtools, menu/shortcut toggle, and copy release artifacts from CARGO_TARGET_DIR.

Co-authored-by: Cursor <cursoragent@cursor.com>

run.sh

@@ -37,7 +37,7 @@ sleep 3
 echo ""
 echo -e "${GREEN}🎉 OpsXShell 已启动！${NC}"
 echo -e "${CYAN}📄 日志: tail -f ${LOG_FILE}${NC}"
-echo -e "${CYAN}🔍 DevTools: 按 Cmd+Option+I (macOS) 或 F12${NC}"
+echo -e "${CYAN}🔍 DevTools: 菜单「视图 → 开发者工具」，或 Cmd+Option+I / F12${NC}"
 
 # 等待子进程
 wait $VITE_PID 2>/dev/null || true