feat(filelib-web): 老师端文件库改网盘式网格浏览(下钻导航+右键菜单)

- 新 GridLibraryView:双击下钻文件夹/项目,面包屑+返回跳级,项目内文件同网格,
  双击进 FileEditor 预览;工具条按上下文出新建文件夹/项目/文件
- 右键菜单(ContextMenu):打开/新建子文件夹/重命名/授权管理/详情/删除,
  按节点 role 动态显隐;文件菜单:打开预览/下载/删除;空白处右键出新建+刷新
- GridCard 大图标卡片(琥珀文件夹/立方体项目/文档文件);授权与详情复用
  GrantsPanel/OverviewPanel(Modal 加 maxW prop);Icon 补 5 个图标
- 管理后台 /database 保留树状 LibraryView 不动;后端零改动

hub/filelib-web/src/lib/GridCard.svelte

@@ -0,0 +1,47 @@
+<script lang="ts">
+  /**
+   * 网盘式大图标卡片:文件夹(琥珀填充)/项目(立方体描边)/文件(文档描边)。
+   * 单击选中、onopen(双击)、oncontextmenu(右键,回传光标坐标)。
+   */
+  let {
+    kind,
+    name,
+    meta = null,
+    selected = false,
+    onselect,
+    onopen,
+    oncontextmenu,
+  }: {
+    kind: "FOLDER" | "PROJECT" | "FILE";
+    name: string;
+    meta?: string | null;
+    selected?: boolean;
+    onselect: () => void;
+    onopen: () => void;
+    oncontextmenu: (x: number, y: number) => void;
+  } = $props();
+</script>
+
+<button
+  class="flex cursor-pointer flex-col items-center gap-1.5 rounded-xl px-2 pb-2 pt-3 select-none {selected
+    ? 'bg-selected'
+    : 'hover:bg-hover'}"
+  onclick={onselect}
+  ondblclick={onopen}
+  oncontextmenu={(e) => { e.preventDefault(); oncontextmenu(e.clientX, e.clientY); }}
+  title={name}
+>
+  <span class="flex h-14 w-14 items-center justify-center">
+    {#if kind === "FOLDER"}
+      <svg width="54" height="54" viewBox="0 0 24 24" fill="#f5c94a" stroke="#d9a92b" stroke-width="0.6" stroke-linejoin="round"><path d="M3 7a2 2 0 0 1 2-2h4l2 2h8a2 2 0 0 1 2 2v9a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V7Z" /></svg>
+    {:else if kind === "PROJECT"}
+      <svg width="50" height="50" viewBox="0 0 24 24" fill="#e8f0ea" stroke="#4a6741" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M20 7l-8-4-8 4m16 0l-8 4m8-4v10l-8 4m0-10L4 7m8 4v10M4 7v10l8 4" /></svg>
+    {:else}
+      <svg width="46" height="46" viewBox="0 0 24 24" fill="#ffffff" stroke="#9c9b96" stroke-width="1.4" stroke-linecap="round" stroke-linejoin="round"><path d="M14 3H7a2 2 0 0 0-2 2v14a2 2 0 0 0 2 2h10a2 2 0 0 0 2-2V8l-5-5Z" /><path d="M14 3v5h5" /><path d="M9 13h6M9 17h6" /></svg>
+    {/if}
+  </span>
+  <span class="line-clamp-2 w-full break-all text-center text-[12.5px] leading-snug text-ink">{name}</span>
+  {#if meta !== null}
+    <span class="-mt-1 text-[10.5px] text-ink-3">{meta}</span>
+  {/if}
+</button>