feat: 实时消息与管理端运营能力

新增群聊/私信与公共 WebSocket 总线，站长用户内容档案，并将通知与待审角标改为推送驱动；同步精简管理仪表盘并修复主题换肤 DOM 冲突。

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

frontend/components/ContextMenu.tsx

@@ -0,0 +1,136 @@
+"use client";
+
+import { useEffect, useRef } from "react";
+
+export type CtxMenuItem = {
+  key: string;
+  label: string;
+  icon?: React.ReactNode;
+  danger?: boolean;
+  disabled?: boolean;
+  onClick: () => void;
+};
+
+/**
+ * 统一右键/长按浮层菜单（飞书式）。
+ * 定位会钳制在视口内；点击外侧或滚动关闭。
+ */
+export default function ContextMenu({
+  x,
+  y,
+  items,
+  onClose,
+}: {
+  x: number;
+  y: number;
+  items: CtxMenuItem[];
+  onClose: () => void;
+}) {
+  const ref = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const close = () => onClose();
+    window.addEventListener("click", close);
+    window.addEventListener("scroll", close, true);
+    window.addEventListener("resize", close);
+    return () => {
+      window.removeEventListener("click", close);
+      window.removeEventListener("scroll", close, true);
+      window.removeEventListener("resize", close);
+    };
+  }, [onClose]);
+
+  useEffect(() => {
+    const el = ref.current;
+    if (!el) return;
+    const rect = el.getBoundingClientRect();
+    let left = x;
+    let top = y;
+    if (left + rect.width > window.innerWidth - 8) {
+      left = Math.max(8, window.innerWidth - rect.width - 8);
+    }
+    if (top + rect.height > window.innerHeight - 8) {
+      top = Math.max(8, window.innerHeight - rect.height - 8);
+    }
+    el.style.left = `${left}px`;
+    el.style.top = `${top}px`;
+  }, [x, y, items]);
+
+  return (
+    <div
+      ref={ref}
+      className="fixed z-[1200] min-w-[148px] rounded-xl py-1 shadow-lg j13-toast-in"
+      style={{
+        left: x,
+        top: y,
+        background: "var(--panel)",
+        border: "1px solid var(--line)",
+      }}
+      onClick={(e) => e.stopPropagation()}
+      onContextMenu={(e) => e.preventDefault()}
+    >
+      {items.map((it) => (
+        <button
+          key={it.key}
+          type="button"
+          disabled={it.disabled}
+          className="w-full flex items-center gap-2.5 px-3.5 py-2 text-[13px] text-left transition-colors disabled:opacity-40"
+          style={{
+            color: it.danger ? "var(--danger)" : "var(--ink)",
+          }}
+          onMouseEnter={(e) => {
+            e.currentTarget.style.background = it.danger
+              ? "var(--danger-soft)"
+              : "var(--accent-soft)";
+          }}
+          onMouseLeave={(e) => {
+            e.currentTarget.style.background = "transparent";
+          }}
+          onClick={() => {
+            if (it.disabled) return;
+            onClose();
+            it.onClick();
+          }}
+        >
+          {it.icon}
+          {it.label}
+        </button>
+      ))}
+    </div>
+  );
+}
+
+/** 绑定桌面右键 + 移动端长按，打开菜单 */
+export function usePressMenu(
+  openAt: (x: number, y: number) => void
+): {
+  onContextMenu: (e: React.MouseEvent) => void;
+  onTouchStart: (e: React.TouchEvent) => void;
+  onTouchEnd: () => void;
+  onTouchMove: () => void;
+} {
+  const timer = useRef<ReturnType<typeof setTimeout> | null>(null);
+  const clear = () => {
+    if (timer.current) {
+      clearTimeout(timer.current);
+      timer.current = null;
+    }
+  };
+  return {
+    onContextMenu: (e) => {
+      e.preventDefault();
+      e.stopPropagation();
+      openAt(e.clientX, e.clientY);
+    },
+    onTouchStart: (e) => {
+      const t = e.touches[0];
+      if (!t) return;
+      clear();
+      timer.current = setTimeout(() => {
+        openAt(t.clientX, t.clientY);
+      }, 480);
+    },
+    onTouchEnd: clear,
+    onTouchMove: clear,
+  };
+}