fix: prevent browser cache from serving stale memo data (#5470)

This fixes a critical data loss issue where users editing the same memo
on multiple devices would overwrite each other's changes due to aggressive
browser caching, particularly in Chromium-based browsers and PWAs.

Changes:
- Backend: Add Cache-Control headers to all API responses to prevent
  browser HTTP caching
- Frontend: Force fresh fetch from server when opening memo editor by
  invalidating React Query cache
- Frontend: Reduce memo query staleTime from 60s to 10s for better
  collaborative editing support

Fixes #5470

server/router/api/v1/connect_interceptors.go

@@ -50,7 +50,19 @@ func (*MetadataInterceptor) WrapUnary(next connect.UnaryFunc) connect.UnaryFunc
 
 		// Set metadata in context so services can use metadata.FromIncomingContext()
 		ctx = metadata.NewIncomingContext(ctx, md)
-		return next(ctx, req)
+
+		// Execute the request
+		resp, err := next(ctx, req)
+
+		// Prevent browser caching of API responses to avoid stale data issues
+		// See: https://github.com/usememos/memos/issues/5470
+		if resp != nil {
+			resp.Header().Set("Cache-Control", "no-cache, no-store, must-revalidate")
+			resp.Header().Set("Pragma", "no-cache")
+			resp.Header().Set("Expires", "0")
+		}
+
+		return resp, err
 	}
 }
 

web/src/components/MemoEditor/hooks/useMemoInit.ts

+import { useQueryClient } from "@tanstack/react-query";
 import { useEffect, useRef } from "react";
+import { memoKeys } from "@/hooks/useMemoQueries";
 import type { Visibility } from "@/types/proto/api/v1/memo_service_pb";
 import type { EditorRefActions } from "../Editor";
 import { cacheService, memoService } from "../services";
@@ -13,6 +15,7 @@ export const useMemoInit = (
   defaultVisibility?: Visibility,
 ) => {
   const { actions, dispatch } = useEditorContext();
+  const queryClient = useQueryClient();
   const initializedRef = useRef(false);
 
   useEffect(() => {
@@ -24,6 +27,10 @@ export const useMemoInit = (
 
       try {
         if (memoName) {
+          // Force refetch from server to prevent stale data issues
+          // See: https://github.com/usememos/memos/issues/5470
+          await queryClient.invalidateQueries({ queryKey: memoKeys.detail(memoName) });
+
           // Load existing memo
           const loadedState = await memoService.load(memoName);
           dispatch(
@@ -58,5 +65,5 @@ export const useMemoInit = (
     };
 
     init();
-  }, [memoName, cacheKey, username, autoFocus, defaultVisibility, actions, dispatch, editorRef]);
+  }, [memoName, cacheKey, username, autoFocus, defaultVisibility, actions, dispatch, editorRef, queryClient]);
 };

web/src/hooks/useMemoQueries.ts

@@ -53,7 +53,7 @@ export function useMemo(name: string, options?: { enabled?: boolean }) {
       return memo;
     },
     enabled: options?.enabled ?? true,
-    staleTime: 1000 * 60, // 1 minute - memos can be edited frequently
+    staleTime: 1000 * 10, // 10 seconds - reduced to prevent stale data in collaborative editing
   });
 }