feat: 知识库标签/实体关联跳转 + 会话重连容错

前端:
- Wiki 标签与实体改为可点击，弹出 RelatedNotesDialog 查看关联知识
- 知识库首次进入自动打开最近笔记，避免空白阅读区
- 流式重连识别 "Run not found"，清理 sessionStorage 残留 key 并静默回退历史

后端:
- 线程鉴权区分 not found / not accessible，并支持 DB 切换产生的孤儿线程认领
- run 查询/join 在内存未命中时回退持久化存储，重启后返回干净的终止 SSE 而非 404

frontend-web/src/components/wiki/RelatedNotesDialog.tsx

@@ -0,0 +1,110 @@
+import { FileText, Hash, Loader2, Sparkles } from "lucide-react";
+
+import {
+  Dialog,
+  DialogContent,
+  DialogDescription,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import { ScrollArea } from "@/components/ui/scroll-area";
+import { useKnowledgeNotes } from "@/core/knowledge/hooks";
+import type { KnowledgeNote } from "@/core/knowledge/types";
+
+import { SOURCE_TYPE_LABELS, formatDateTime } from "./wikiUtils";
+
+/** What was clicked: a tag (exact filter) or an entity (keyword match in body). */
+export type RelatedNotesFilter =
+  | { kind: "tag"; value: string }
+  | { kind: "entity"; value: string };
+
+/**
+ * Click a tag / entity chip → list every other note that shares it.
+ * Tags use the backend's exact `tag` filter; entities fall back to a keyword
+ * match (entity names appear verbatim in titles/summaries/bodies).
+ */
+export function RelatedNotesDialog({
+  filter,
+  currentNoteId,
+  onOpenChange,
+  onSelect,
+}: {
+  filter: RelatedNotesFilter | null;
+  currentNoteId?: string;
+  onOpenChange: (open: boolean) => void;
+  onSelect: (noteId: string) => void;
+}) {
+  const params =
+    filter?.kind === "tag"
+      ? { tag: filter.value, limit: 50 }
+      : filter?.kind === "entity"
+        ? { keyword: filter.value, limit: 50 }
+        : { limit: 0 };
+
+  const { data, isLoading, isFetching } = useKnowledgeNotes(params);
+  const items = (data?.items ?? []).filter(
+    (n: KnowledgeNote) => n.id !== currentNoteId,
+  );
+
+  return (
+    <Dialog open={!!filter} onOpenChange={onOpenChange}>
+      <DialogContent className="max-w-lg">
+        <DialogHeader>
+          <DialogTitle className="flex items-center gap-2">
+            {filter?.kind === "entity" ? (
+              <Sparkles className="size-4 text-violet-500" />
+            ) : (
+              <Hash className="size-4 text-rose-500" />
+            )}
+            <span className="truncate">{filter?.value}</span>
+          </DialogTitle>
+          <DialogDescription>
+            {filter?.kind === "entity"
+              ? "提到该实体的关联知识"
+              : "使用该标签的关联知识"}
+          </DialogDescription>
+        </DialogHeader>
+
+        <ScrollArea className="max-h-[55vh]">
+          {isLoading || (isFetching && items.length === 0) ? (
+            <div className="text-muted-foreground flex items-center gap-2 p-4 text-sm">
+              <Loader2 className="size-4 animate-spin" /> 加载中...
+            </div>
+          ) : items.length === 0 ? (
+            <div className="text-muted-foreground rounded-md border border-dashed p-6 text-center text-sm">
+              暂无其他关联知识。
+            </div>
+          ) : (
+            <ul className="flex flex-col gap-1 pr-2">
+              {items.map((note) => (
+                <li key={note.id}>
+                  <button
+                    type="button"
+                    onClick={() => onSelect(note.id)}
+                    className="flex w-full flex-col gap-0.5 rounded-md border border-transparent px-3 py-2 text-left transition-colors hover:border-slate-200 hover:bg-slate-50 dark:hover:border-slate-700 dark:hover:bg-slate-800/60"
+                  >
+                    <span className="flex items-center gap-2 text-sm font-medium text-slate-800 dark:text-slate-100">
+                      <FileText className="size-3.5 shrink-0 text-slate-400" />
+                      <span className="truncate">{note.title}</span>
+                    </span>
+                    {note.summary ? (
+                      <span className="line-clamp-2 pl-[1.375rem] text-xs text-slate-500 dark:text-slate-400">
+                        {note.summary}
+                      </span>
+                    ) : null}
+                    <span className="text-muted-foreground pl-[1.375rem] text-[11px]">
+                      {SOURCE_TYPE_LABELS[note.source_type] ?? note.source_type}
+                      {note.updated_at
+                        ? ` · ${formatDateTime(note.updated_at).slice(0, 10)}`
+                        : ""}
+                    </span>
+                  </button>
+                </li>
+              ))}
+            </ul>
+          )}
+        </ScrollArea>
+      </DialogContent>
+    </Dialog>
+  );
+}

frontend-web/src/components/wiki/WikiContent.tsx

@@ -25,6 +25,10 @@ import { DocumentToolbar } from "./DocumentToolbar";
 import { FloatingToc } from "./FloatingToc";
 import { MarkdownViewer } from "./MarkdownViewer";
 import { RelatedDocs } from "./RelatedDocs";
+import {
+  RelatedNotesDialog,
+  type RelatedNotesFilter,
+} from "./RelatedNotesDialog";
 import {
   SOURCE_TYPE_LABELS,
   STATUS_LABELS,
@@ -91,6 +95,10 @@ export function WikiContent({
   const [draftContent, setDraftContent] = useState(note.content_md);
   const [draftStatus, setDraftStatus] = useState<string>(note.status);
   const [activeHeadingId, setActiveHeadingId] = useState<string | null>(null);
+  // Tag / entity chip clicked → show notes that share it.
+  const [relatedFilter, setRelatedFilter] = useState<RelatedNotesFilter | null>(
+    null,
+  );
 
   // Pull the backend-injected `## Related` wikilinks out of the body so they
   // render as a structured module; editing still works on the full source.
@@ -270,12 +278,15 @@ export function WikiContent({
                     <MetaTag>创建：{formatDateTime(note.created_at).slice(0, 10)}</MetaTag>
                   ) : null}
                   {note.tags.map((tag) => (
-                    <span
+                    <button
                       key={tag}
-                      className="inline-flex h-6 items-center rounded-md bg-rose-50 px-2 text-xs font-medium text-rose-500 dark:bg-rose-500/10 dark:text-rose-300"
+                      type="button"
+                      title={`查看「${tag}」的关联知识`}
+                      onClick={() => setRelatedFilter({ kind: "tag", value: tag })}
+                      className="inline-flex h-6 cursor-pointer items-center rounded-md bg-rose-50 px-2 text-xs font-medium text-rose-500 transition-colors hover:bg-rose-100 hover:text-rose-600 dark:bg-rose-500/10 dark:text-rose-300 dark:hover:bg-rose-500/20"
                     >
                       #{tag}
-                    </span>
+                    </button>
                   ))}
                 </div>
 
@@ -287,11 +298,15 @@ export function WikiContent({
                     {note.entities.map((ent) => {
                       const meta = entityMeta(ent.entity_type);
                       return (
-                        <span
+                        <button
                           key={`${ent.name}-${ent.entity_type ?? ""}`}
-                          title={meta.label}
+                          type="button"
+                          title={`查看与「${ent.name}」(${meta.label})相关的知识`}
+                          onClick={() =>
+                            setRelatedFilter({ kind: "entity", value: ent.name })
+                          }
                           className={cn(
-                            "inline-flex items-center gap-1.5 rounded-full border py-1 pl-2 pr-1 text-xs font-medium",
+                            "inline-flex cursor-pointer items-center gap-1.5 rounded-full border py-1 pl-2 pr-1 text-xs font-medium transition-opacity hover:opacity-80",
                             meta.className,
                           )}
                         >
@@ -300,7 +315,7 @@ export function WikiContent({
                           <span className="rounded-full bg-current/15 px-1.5 py-0.5 text-[10px] leading-none opacity-90">
                             {meta.label}
                           </span>
-                        </span>
+                        </button>
                       );
                     })}
                   </div>
@@ -373,6 +388,18 @@ export function WikiContent({
           </div>
         </div>
       </div>
+
+      <RelatedNotesDialog
+        filter={relatedFilter}
+        currentNoteId={note.id}
+        onOpenChange={(open) => {
+          if (!open) setRelatedFilter(null);
+        }}
+        onSelect={(id) => {
+          setRelatedFilter(null);
+          navigate(`/page/workspace/knowledge/${id}`);
+        }}
+      />
     </div>
   );
 }

frontend-web/src/core/threads/hooks.ts

@@ -152,7 +152,10 @@ function getStreamErrorMessage(error: unknown): string {
  */
 function isThreadNotAccessibleError(message: string): boolean {
   const lowered = message.toLowerCase();
-  if (/thread\s+[\w-]{8,}\s+not\s+found/i.test(message)) {
+  // Backend now returns "not found" (no row + no checkpoint) and
+  // "not accessible" (row owned by another user / stale login session) as
+  // distinct details — both mean the current user can't use this thread.
+  if (/thread\s+[\w-]{8,}\s+not\s+(found|accessible)/i.test(message)) {
     return true;
   }
   // Fallback: a bare 404/403 from the threads endpoint when the SDK has
@@ -163,6 +166,21 @@ function isThreadNotAccessibleError(message: string): boolean {
   );
 }
 
+/**
+ * Detect a "Run <id> not found" 404 from the LangGraph SDK.
+ *
+ * The SDK persists the in-flight run id under ``lg:stream:{threadId}`` in
+ * sessionStorage and, on mount, auto-``joinStream``s it to resume a dropped
+ * SSE. After a backend restart the in-memory run registry is gone, so the join
+ * 404s — and the SDK only clears that key on reconnect *success*, never on
+ * failure. So every switch back into the conversation re-fires the same 404.
+ * We detect it here to clear the stale key ourselves and stay silent (the
+ * conversation renders from history; there is nothing live to reconnect to).
+ */
+function isRunNotFoundError(message: string): boolean {
+  return /run\s+[\w-]{8,}\s+not\s+found/i.test(message);
+}
+
 function buildCurrentUserLabel(): string {
   const auth = getStoredAuth();
   if (!auth) {
@@ -335,6 +353,19 @@ export function useThreadStream({
     onError(error) {
       setOptimisticMessages([]);
       const message = getStreamErrorMessage(error);
+      // A stale auto-reconnect ("Run <id> not found") after a backend restart:
+      // drop the dirty ``lg:stream:{threadId}`` key so switching back into this
+      // conversation stops re-firing the same 404, and render from history
+      // silently — there is no live run to rejoin.
+      if (isRunNotFoundError(message)) {
+        const staleThreadId = threadIdRef.current ?? onStreamThreadId ?? null;
+        if (staleThreadId && runMetadataStorageRef.current) {
+          runMetadataStorageRef.current.removeItem(
+            `lg:stream:${staleThreadId}`,
+          );
+        }
+        return;
+      }
       // A "thread not found" 404 almost always means the URL points at a
       // thread from a previous login session — either this tab outlived a
       // logout/re-login or the thread genuinely belongs to a different user.

frontend-web/src/pages/KnowledgeBasePage.tsx

@@ -468,6 +468,8 @@ export default function KnowledgeBasePage() {
   const [status, setStatus] = useState("all");
   const [expandedIds, setExpandedIds] = useState<Set<string>>(new Set());
   const treeInitializedRef = useRef(false);
+  // Auto-open a default note once on entry so the reading pane is never blank.
+  const defaultNoteShownRef = useRef(false);
   const [mobileSidebarOpen, setMobileSidebarOpen] = useState(false);
   const [sidebarCollapsed, setSidebarCollapsed] = useState(readSidebarCollapsed);
 
@@ -495,6 +497,15 @@ export default function KnowledgeBasePage() {
   const { data: note, isLoading: noteLoading } = useKnowledgeNote(noteId);
   const { data: wikiLinks } = useNoteWikilinks(noteId);
 
+  // On first entry without an explicit note, open the most recent one so the
+  // reading pane shows real content instead of the empty placeholder.
+  useEffect(() => {
+    if (defaultNoteShownRef.current || noteId || isLoading) return;
+    if (notes.length === 0) return;
+    defaultNoteShownRef.current = true;
+    navigate(`/page/workspace/knowledge/${notes[0].id}`, { replace: true });
+  }, [noteId, isLoading, notes, navigate]);
+
   // First load: expand the root-level folders so the tree reads as a directory.
   useEffect(() => {
     if (treeInitializedRef.current || tree.length === 0) return;