♻️ refactor(sidebar): 清理 V2 rail 残留死代码

- 删除未被调用的 rail connection button/group 渲染闭包

- 移除对应的折叠、拖拽状态和 badge/host 辅助函数

- 保留当前可达的 active connection 状态展示和树拖拽排序逻辑

frontend/src/components/Sidebar.tsx

@@ -46,7 +46,6 @@ import { Tree, message, Dropdown, MenuProps, Input, Button, Form, Badge, Checkbo
   FolderAddOutlined,
   SaveOutlined,
   EditOutlined,
-  DownOutlined,
   SearchOutlined,
   KeyOutlined,
   ThunderboltOutlined,
@@ -1190,18 +1189,6 @@ const Sidebar: React.FC<{
   const allSavedQueriesNode = useMemo<TreeNode | null>(() => {
       return buildAllSavedQueriesTreeNode(savedQueries, connections);
   }, [connections, savedQueries]);
-  const v2RailConnectionGroups = useMemo(
-      () => buildV2RailConnectionGroups(connections, connectionTags, sidebarRootOrder),
-      [connections, connectionTags, sidebarRootOrder],
-  );
-  const [collapsedV2RailGroupIds, setCollapsedV2RailGroupIds] = useState<string[]>([]);
-  const collapsedV2RailGroupIdSet = useMemo(
-      () => new Set(collapsedV2RailGroupIds),
-      [collapsedV2RailGroupIds],
-  );
-  const hasV2RailConnectionGroups = v2RailConnectionGroups.some((group) => !group.isUngrouped);
-  const [draggingV2RailRootToken, setDraggingV2RailRootToken] = useState('');
-
   const snapshotTreeSelectionBeforeDrag = useCallback(() => {
       treeDragSelectionSnapshotRef.current = {
           selectedKeys: [...selectedKeys],
@@ -6828,101 +6815,6 @@ const Sidebar: React.FC<{
       return connectionStatusMap.get(connectionId) || 'idle';
   }, [connectionStatusMap]);
 
-  const toggleV2RailConnectionGroup = useCallback((groupId: string) => {
-      setCollapsedV2RailGroupIds((prev) => (
-          prev.includes(groupId)
-              ? prev.filter((id) => id !== groupId)
-              : [...prev, groupId]
-      ));
-  }, []);
-
-  const handleV2RailRootDrop = useCallback((
-      sourceToken: string,
-      targetToken: string,
-      insertBefore: boolean,
-  ) => {
-      if (!sourceToken || !targetToken || sourceToken === targetToken) {
-          return;
-      }
-      reorderSidebarRoot(sourceToken, targetToken, insertBefore);
-  }, [reorderSidebarRoot]);
-
-  const getRailConnectionTypeLabel = (conn: SavedConnection): string => {
-      const iconType = resolveConnectionIconType(conn);
-      if (iconType === 'mysql' || iconType === 'mariadb' || iconType === 'oceanbase') return 'MY';
-      if (iconType === 'postgres') return 'PG';
-      if (iconType === 'gaussdb') return 'GS';
-      if (iconType === 'redis') return 'R';
-      if (iconType === 'mongodb') return 'MO';
-      if (iconType === 'oracle') return 'OR';
-      if (iconType === 'sqlserver') return 'SS';
-      if (iconType === 'starrocks') return 'SR';
-      if (iconType === 'sqlite') return 'SQ';
-      if (iconType === 'jvm') return 'JV';
-      return iconType.slice(0, 2).toUpperCase() || 'DB';
-  };
-
-  const getRailConnectionHostLabel = (conn: SavedConnection): string => {
-      const hostTokens = resolveConnectionHostTokens(conn.config);
-      const primaryHost = String(hostTokens[0] || '').trim().replace(/^\[|\]$/g, '');
-      if (primaryHost) {
-          if (/^(localhost|127(?:\.\d{1,3}){3}|0\.0\.0\.0)$/i.test(primaryHost)) {
-              return 'LO';
-          }
-          if (/^\d{1,3}(?:\.\d{1,3}){3}$/.test(primaryHost)) {
-              const lastSegment = primaryHost.split('.').pop() || '';
-              return lastSegment.slice(-3).toUpperCase() || 'IP';
-          }
-          if (primaryHost.includes(':') && /^[a-f0-9:]+$/i.test(primaryHost)) {
-              const lastSegment = primaryHost.split(':').filter(Boolean).pop() || '';
-              return lastSegment.slice(-3).toUpperCase() || 'IP';
-          }
-
-          const hostFragments = primaryHost
-              .split(/[^a-z0-9\u4e00-\u9fa5]+/i)
-              .map((entry) => entry.trim())
-              .filter(Boolean);
-          if (hostFragments.length >= 2) {
-              return `${hostFragments[0][0] || ''}${hostFragments[1][0] || ''}`.toUpperCase();
-          }
-          const hostToken = hostFragments[0] || primaryHost.split('.')[0] || '';
-          if (hostToken) {
-              return hostToken.replace(/[^a-z0-9\u4e00-\u9fa5]/gi, '').slice(0, 3).toUpperCase() || 'DB';
-          }
-      }
-
-      return getRailConnectionTypeLabel(conn);
-  };
-
-  const getRailConnectionBadgeLabel = (conn: SavedConnection): string => {
-      const connectionName = String(conn.name || '').trim();
-      const cjkParts = connectionName.match(/[\u4e00-\u9fa5]/g);
-      if (cjkParts && cjkParts.length > 0) {
-          return cjkParts.slice(0, 2).join('');
-      }
-
-      const latinTokens = connectionName.match(/[a-z0-9]+/gi) || [];
-      if (latinTokens.length >= 2) {
-          const firstToken = latinTokens[0] || '';
-          const secondToken = latinTokens[1] || '';
-          return `${firstToken[0] || ''}${secondToken[0] || ''}`.toUpperCase();
-      }
-      if (latinTokens.length === 1) {
-          const token = latinTokens[0];
-          const alphaPrefix = token.match(/^[a-z]+/i)?.[0] || '';
-          if (alphaPrefix) {
-              return alphaPrefix.slice(0, 3).toUpperCase();
-          }
-          const trailingDigits = token.match(/(\d{2,})$/)?.[1];
-          if (trailingDigits) {
-              return trailingDigits.slice(-3).toUpperCase();
-          }
-          return token.slice(0, 3).toUpperCase();
-      }
-
-      return getRailConnectionTypeLabel(conn);
-  };
-
   const openV2ConnectionContextMenu = (
       event: React.MouseEvent,
       connOrNode: SavedConnection | TreeNode,
@@ -8893,165 +8785,6 @@ const Sidebar: React.FC<{
       }
   };
 
-  const renderV2RailConnectionButton = (conn: SavedConnection) => {
-      const accent = resolveConnectionAccentColor(conn);
-      const status = buildRailConnectionStatus(conn.id);
-      const badgeLabel = getRailConnectionBadgeLabel(conn);
-      const hostLabel = getRailConnectionHostLabel(conn);
-      const title = `${conn.name} · ${resolveConnectionHostSummary(conn.config) || conn.config.type}`;
-      const rootToken = buildSidebarRootConnectionToken(conn.id);
-
-      return (
-          <Tooltip key={conn.id} title={title} placement="right">
-              <button
-                  type="button"
-                  className={`gn-v2-rail-item${conn.id === activeConnectionId ? ' is-active' : ''}`}
-                  draggable
-                  onDragStart={(event) => {
-                      snapshotTreeSelectionBeforeDrag();
-                      treeDragSelectSuppressUntilRef.current = Date.now() + 600;
-                      setDraggingV2RailRootToken(rootToken);
-                      setIsTreeDragging(true);
-                      event.dataTransfer.effectAllowed = 'move';
-                      event.dataTransfer.setData('text/plain', rootToken);
-                  }}
-                  onDragEnd={() => {
-                      restoreTreeSelectionAfterDrag();
-                      setDraggingV2RailRootToken('');
-                      setIsTreeDragging(false);
-                  }}
-                  onDragOver={(event) => {
-                      if (!draggingV2RailRootToken || draggingV2RailRootToken === rootToken) {
-                          return;
-                      }
-                      event.preventDefault();
-                      event.stopPropagation();
-                      event.dataTransfer.dropEffect = 'move';
-                  }}
-                  onDrop={(event) => {
-                      if (!draggingV2RailRootToken || draggingV2RailRootToken === rootToken) {
-                          return;
-                      }
-                      event.preventDefault();
-                      event.stopPropagation();
-                      const rect = event.currentTarget.getBoundingClientRect();
-                      const insertBefore = event.clientY < rect.top + rect.height / 2;
-                      handleV2RailRootDrop(draggingV2RailRootToken, rootToken, insertBefore);
-                      restoreTreeSelectionAfterDrag();
-                      setDraggingV2RailRootToken('');
-                      setIsTreeDragging(false);
-                  }}
-                  onClick={() => selectConnectionFromRail(conn)}
-                  onContextMenu={(event) => openV2ConnectionContextMenu(event, conn)}
-                  aria-label={`切换到连接 ${conn.name}`}
-                  title={title}
-                  data-v2-rail-host-context-menu-trigger="true"
-              >
-                  <span className="gn-v2-rail-active-bar" />
-                  <span className="gn-v2-rail-badge-wrap">
-                      <span className="gn-v2-rail-badge" style={{ background: accent }}>
-                          {badgeLabel}
-                      </span>
-                      <span className={`gn-v2-rail-status is-${status}`} />
-                  </span>
-                  <span className="gn-v2-rail-fallback">{hostLabel}</span>
-              </button>
-          </Tooltip>
-      );
-  };
-
-  const renderV2RailConnectionGroup = (group: V2RailConnectionGroup) => {
-      const collapsed = collapsedV2RailGroupIdSet.has(group.id);
-      const groupTitle = group.name || t('connection.sidebar.group.untitled');
-      const rootToken = group.rootToken;
-
-      return (
-          <div
-              key={group.id}
-              className={`gn-v2-rail-group${group.isUngrouped ? ' is-ungrouped' : ''}${collapsed ? ' is-collapsed' : ''}`}
-              data-v2-rail-connection-group="true"
-              draggable
-              onDragStart={(event) => {
-                  snapshotTreeSelectionBeforeDrag();
-                  treeDragSelectSuppressUntilRef.current = Date.now() + 600;
-                  setDraggingV2RailRootToken(rootToken);
-                  setIsTreeDragging(true);
-                  event.dataTransfer.effectAllowed = 'move';
-                  event.dataTransfer.setData('text/plain', rootToken);
-              }}
-              onDragEnd={() => {
-                  restoreTreeSelectionAfterDrag();
-                  setDraggingV2RailRootToken('');
-                  setIsTreeDragging(false);
-              }}
-              onDragOver={(event) => {
-                  if (!draggingV2RailRootToken || draggingV2RailRootToken === rootToken) {
-                      return;
-                  }
-                  event.preventDefault();
-                  event.stopPropagation();
-                  event.dataTransfer.dropEffect = 'move';
-              }}
-              onDrop={(event) => {
-                  if (!draggingV2RailRootToken || draggingV2RailRootToken === rootToken) {
-                      return;
-                  }
-                  event.preventDefault();
-                  event.stopPropagation();
-                  const rect = event.currentTarget.getBoundingClientRect();
-                  const insertBefore = event.clientY < rect.top + rect.height / 2;
-                  handleV2RailRootDrop(draggingV2RailRootToken, rootToken, insertBefore);
-                  restoreTreeSelectionAfterDrag();
-                  setDraggingV2RailRootToken('');
-                  setIsTreeDragging(false);
-              }}
-          >
-              {hasV2RailConnectionGroups && (
-                  <Tooltip title={t('connection.sidebar.group.meta', { count: group.connections.length.toLocaleString() })} placement="right">
-                      <button
-                          type="button"
-                          className={`gn-v2-rail-group-header${group.isUngrouped ? ' is-ungrouped' : ''}`}
-                          onClick={() => toggleV2RailConnectionGroup(group.id)}
-                          onContextMenu={(event) => {
-                              if (group.isUngrouped) return;
-                              event.preventDefault();
-                              event.stopPropagation();
-                              const position = resolveSidebarContextMenuPosition(event.clientX, event.clientY);
-                              setContextMenu({
-                                  x: position.x,
-                                  y: position.y,
-                                  sourceX: event.clientX,
-                                  sourceY: event.clientY,
-                                  items: [],
-                                  kind: 'v2-connection-group',
-                                  node: group,
-                                  rootClassName: 'gn-v2-table-context-menu-popup',
-                                  overlayStyle: { width: 264, maxWidth: 'calc(100vw - 24px)' },
-                                  maxHeight: position.maxHeight,
-                              });
-                          }}
-                          aria-label={t(collapsed ? 'connection.sidebar.group.expandAria' : 'connection.sidebar.group.collapseAria', { name: groupTitle })}
-                          aria-expanded={!collapsed}
-                          title={t('connection.sidebar.group.meta', { count: group.connections.length.toLocaleString() })}
-                          data-v2-rail-connection-group-header="true"
-                      >
-                          <span className="gn-v2-rail-group-chevron">
-                              <DownOutlined />
-                          </span>
-                          <span className="gn-v2-rail-group-title">{groupTitle}</span>
-                          <span className="gn-v2-rail-group-count">{group.connections.length}</span>
-                      </button>
-                  </Tooltip>
-              )}
-              {!collapsed && (
-                  <div className="gn-v2-rail-group-items">
-                      {group.connections.map(renderV2RailConnectionButton)}
-                  </div>
-              )}
-          </div>
-      );
-  };
-
   const v2RailObjectActionsLabel = t('sidebar.rail.object_actions');
   const v2RailSystemActionsLabel = t('sidebar.rail.system_actions');
   const v2NewGroupLabel = t('sidebar.action.new_group');