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/app/api/brainstorm/[sessionId]/finalize/route.ts

@@ -0,0 +1,98 @@
+import { NextRequest, NextResponse } from 'next/server'
+import prisma from '@/lib/prisma'
+import { auth } from '@/auth'
+
+export async function POST(
+  request: NextRequest,
+  { params }: { params: Promise<{ sessionId: string }> }
+) {
+  const session = await auth()
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+  }
+
+  try {
+    const { sessionId } = await params
+
+    const brainstormSession = await prisma.brainstormSession.findFirst({
+      where: {
+        id: sessionId,
+        OR: [
+          { userId: session.user.id },
+          { participants: { some: { userId: session.user.id } } },
+        ],
+      },
+      include: {
+        ideas: {
+          include: {
+            noteRefs: {
+              include: {
+                note: { select: { id: true, title: true, labels: true } },
+              },
+            },
+          },
+        },
+      },
+    })
+
+    if (!brainstormSession) {
+      return NextResponse.json({ error: 'Session not found' }, { status: 404 })
+    }
+
+    const noteImpactMap = new Map<string, { title: string; labels: string[]; acceptedCount: number; dismissedCount: number }>()
+
+    for (const idea of brainstormSession.ideas) {
+      for (const ref of idea.noteRefs) {
+        if (!ref.noteId || !ref.note) continue
+        const existing = noteImpactMap.get(ref.noteId) || {
+          title: ref.note.title || 'Untitled',
+          labels: (() => { try { return JSON.parse(ref.note.labels || '[]') } catch { return [] } })(),
+          acceptedCount: 0,
+          dismissedCount: 0,
+        }
+        if (ref.verdict === 'accepted') existing.acceptedCount++
+        else if (ref.verdict === 'dismissed') existing.dismissedCount++
+        noteImpactMap.set(ref.noteId, existing)
+      }
+    }
+
+    const updatePromises: Promise<any>[] = []
+
+    for (const [noteId, impact] of noteImpactMap) {
+      if (impact.acceptedCount === 0 && impact.dismissedCount > 0) {
+        if (!impact.labels.includes('brainstorm-dry')) {
+          impact.labels.push('brainstorm-dry')
+          updatePromises.push(
+            prisma.note.update({
+              where: { id: noteId },
+              data: { labels: JSON.stringify(impact.labels) },
+            })
+          )
+        }
+      }
+    }
+
+    if (updatePromises.length > 0) {
+      await prisma.$transaction(updatePromises)
+    }
+
+    const fruitful = Array.from(noteImpactMap.values()).filter(n => n.acceptedCount > 0).length
+    const dry = Array.from(noteImpactMap.values()).filter(n => n.acceptedCount === 0 && n.dismissedCount > 0).length
+    const totalRefs = Array.from(noteImpactMap.values()).length
+
+    return NextResponse.json({
+      success: true,
+      impact: {
+        notesSolicited: totalRefs,
+        notesEnriched: fruitful,
+        notesMarkedDry: dry,
+      },
+    })
+  } catch (error) {
+    console.error('Error finalizing brainstorm:', error)
+    return NextResponse.json(
+      { error: 'Failed to finalize brainstorm' },
+      { status: 500 }
+    )
+  }
+}