feat: brainstorm sessions, PDF document Q&A, embedding fixes, and UI improvements

- Add brainstorm feature with collaborative canvas, AI idea generation, live cursors, playback, and export
- Add PDF upload/extraction/ingestion pipeline with pgvector document search (RAG)
- Add document Q&A overlay with streaming chat and PDF preview
- Add note attachments UI with status polling, grid layout, and auto-scroll
- Add task extraction AI tool and agent executor improvements
- Fix NoteEmbedding missing updatedAt column, re-index 66 notes with 1536-dim embeddings
- Fix brainstorm 'Create Note' button: add success toast and redirect to created note
- Fix memory echo notification infinite polling
- Fix chat route to always include document_search tool
- Add brainstorm i18n keys across all 14 locales
- Add socket server for real-time brainstorm collaboration
- Add hierarchical notebook selector and organize notebook dialog improvements
- Add sidebar brainstorm section with session management
- Update prisma schema with brainstorm tables, attachments, and document chunks

memento-note/hooks/use-brainstorm-socket.ts

@@ -0,0 +1,107 @@
+'use client'
+
+import { useEffect, useRef, useState, useCallback } from 'react'
+import { io, Socket } from 'socket.io-client'
+
+export interface PresenceUser {
+  userId: string
+  name: string
+  cursor: { x: number; y: number } | null
+  color: string
+}
+
+export interface ActivityEvent {
+  action: string
+  userId: string
+  userName: string
+  details: any
+}
+
+const SOCKET_URL = process.env.NEXT_PUBLIC_SOCKET_URL || 'http://localhost:3001'
+
+export function useBrainstormSocket(
+  sessionId: string | null,
+  userId: string | null,
+  userName: string | null,
+  onIdeaMoved?: (data: { ideaId: string; positionX: number; positionY: number }) => void
+) {
+  const socketRef = useRef<Socket | null>(null)
+  const onIdeaMovedRef = useRef(onIdeaMoved)
+  onIdeaMovedRef.current = onIdeaMoved
+  const [others, setOthers] = useState<PresenceUser[]>([])
+  const [activities, setActivities] = useState<ActivityEvent[]>([])
+  const [aiProcessingNodeId, setAiProcessingNodeId] = useState<string | null>(null)
+
+  const effectiveUserId = userId || `guest_${Math.random().toString(36).slice(2, 10)}`
+
+  useEffect(() => {
+    if (!sessionId) return
+
+    const socket = io(SOCKET_URL, {
+      auth: {
+        userId: effectiveUserId,
+        sessionId,
+        name: userName || 'Guest',
+        isGuest: !userId,
+      },
+      transports: ['websocket'],
+      autoConnect: true,
+    })
+
+    socketRef.current = socket
+
+    socket.on('presence:update', (users: PresenceUser[]) => {
+      setOthers(users.filter(u => u.userId !== effectiveUserId))
+    })
+
+    socket.on('cursor:update', (data: { userId: string; cursor: { x: number; y: number } }) => {
+      setOthers(prev => prev.map(u =>
+        u.userId === data.userId ? { ...u, cursor: data.cursor } : u
+      ))
+    })
+
+    socket.on('activity:new', (event: ActivityEvent) => {
+      setActivities(prev => [event, ...prev].slice(0, 50))
+    })
+
+    socket.on('idea:added', () => {})
+    socket.on('idea:dismissed', () => {})
+    socket.on('idea:moved', (data: { ideaId: string; positionX: number; positionY: number }) => {
+      onIdeaMovedRef.current?.(data)
+    })
+
+    socket.on('idea:ai_processing', (data: { ideaId: string }) => {
+      setAiProcessingNodeId(data.ideaId)
+    })
+
+    socket.on('idea:ai_completed', (data: { ideaId: string }) => {
+      setAiProcessingNodeId(prev => prev === data.ideaId ? null : prev)
+    })
+
+    socket.on('idea:ai_failed', (data: { ideaId: string }) => {
+      setAiProcessingNodeId(prev => prev === data.ideaId ? null : prev)
+    })
+
+    return () => {
+      socket.disconnect()
+      socketRef.current = null
+      setOthers([])
+      setAiProcessingNodeId(null)
+    }
+  }, [sessionId, effectiveUserId, userName])
+
+  const moveCursor = useCallback((cursor: { x: number; y: number } | null) => {
+    socketRef.current?.emit('cursor:move', cursor)
+  }, [])
+
+  const broadcastActivity = useCallback((action: string, details?: any) => {
+    socketRef.current?.emit('activity:new', {
+      action,
+      userId: effectiveUserId,
+      userName: userName || 'Guest',
+      details,
+    })
+  }, [effectiveUserId, userName])
+
+  return { others, activities, moveCursor, broadcastActivity, socketRef, aiProcessingNodeId }
+}