feat: unify workspace sidebar and create Foundry graph pages

src/components/workspace/graph-page.tsx

@@ -0,0 +1,58 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useRouter, useSearchParams } from "next/navigation";
+import { Network } from "lucide-react";
+import { api, errorText } from "@/lib/api";
+import { readDemoBoards } from "@/lib/demo-workspace";
+import type { Board } from "@/lib/workspace";
+import styles from "./workspace.module.css";
+
+export default function GraphPage({ workspaceId, boardId }: { workspaceId: string; boardId: string }) {
+  const demo = useSearchParams().get("demo") === "1";
+  const router = useRouter();
+  const [board, setBoard] = useState<Board | null>(null);
+  const [error, setError] = useState("");
+
+  useEffect(() => {
+    setBoard(null);
+    setError("");
+    if (demo) {
+      try {
+        const list = readDemoBoards(workspaceId);
+        const item = list.find((b) => b.id === boardId);
+        if (item) setBoard(item);
+        else setError("图谱不存在。");
+      } catch { setError("无法读取本地演示图谱。"); }
+      return;
+    }
+    let active = true;
+    const controller = new AbortController();
+    api<Board>(`workspaces/${encodeURIComponent(workspaceId)}/materials/${encodeURIComponent(boardId)}`, { signal: controller.signal })
+      .then((item) => {
+        if (!active) return;
+        if (item.kind !== "board" || item.workspace_id !== workspaceId) {
+          setError("当前页面不是此工作空间的图谱。");
+          return;
+        }
+        setBoard(item);
+      })
+      .catch((e) => {
+        if (!active) return;
+        setError(errorText(e));
+        if (e.message === "invalid_session") router.replace("/login");
+      });
+    return () => { active = false; controller.abort(); };
+  }, [workspaceId, boardId, demo, router]);
+
+  return (
+    <main className={styles.graph} aria-label="无限图谱">
+      {error ? <p className={styles.graphStatus} role="alert">{error}</p> : board ? (
+        <>
+          <header className={styles.graphHeader}><Network size={16} /><h1>{board.title}</h1>{demo && <span>演示</span>}</header>
+          <div className={styles.graphSurface} aria-label={board.title + "的空白图谱"} />
+        </>
+      ) : <p className={styles.graphStatus} role="status">正在打开图谱…</p>}
+    </main>
+  );
+}