fix(chat): remove 50-source cap from notebook chat context (#628)

* fix(chat): remove 50-source cap from notebook chat context

ChatColumn was independently fetching sources via useSources() which
defaults to a limit of 50 from the API. This caused the chat context
to always be capped at 50 sources regardless of how many are in the
notebook.

ChatColumn now receives sources as a prop from the parent NotebookPage,
which already fetches all sources via useNotebookSources with infinite
scroll pagination.

* test(chat): update ChatColumn tests for new sources prop interface

frontend/src/app/(dashboard)/notebooks/[id]/page.tsx

@@ -185,6 +185,8 @@ export default function NotebookPage() {
                   <ChatColumn
                     notebookId={notebookId}
                     contextSelections={contextSelections}
+                    sources={sources}
+                    sourcesLoading={sourcesLoading}
                   />
                 )}
               </div>
@@ -234,6 +236,8 @@ export default function NotebookPage() {
               <ChatColumn
                 notebookId={notebookId}
                 contextSelections={contextSelections}
+                sources={sources}
+                sourcesLoading={sourcesLoading}
               />
             </div>
           </div>

frontend/src/app/(dashboard)/notebooks/components/ChatColumn.test.tsx

@@ -1,26 +1,16 @@
 import { render, screen } from '@testing-library/react'
 import { describe, it, expect, vi } from 'vitest'
 import { ChatColumn } from './ChatColumn'
-import { useSources } from '@/lib/hooks/use-sources'
 import { useNotes } from '@/lib/hooks/use-notes'
 import { useNotebookChat } from '@/lib/hooks/useNotebookChat'
 
 // Mock the hooks
-vi.mock('@/lib/hooks/use-sources')
 vi.mock('@/lib/hooks/use-notes')
 vi.mock('@/lib/hooks/useNotebookChat')
 vi.mock('@/components/source/ChatPanel', () => ({
   ChatPanel: () => <div data-testid="chat-panel" />
 }))
 
-// Type-safe mock factory for useSources hook
-function createSourcesMock(overrides: { isLoading?: boolean } = {}) {
-  return {
-    data: [],
-    isLoading: overrides.isLoading ?? false,
-  } as unknown as ReturnType<typeof useSources>
-}
-
 // Type-safe mock factory for useNotes hook
 function createNotesMock(overrides: { isLoading?: boolean } = {}) {
   return {
@@ -42,32 +32,31 @@ function createChatMock() {
 }
 
 describe('ChatColumn', () => {
-  const mockProps = {
+  const baseProps = {
     notebookId: 'test-notebook',
     contextSelections: {
       sources: {},
       notes: {}
-    }
+    },
+    sources: [],
   }
 
   it('shows loading spinner when fetching data', () => {
-    vi.mocked(useSources).mockReturnValue(createSourcesMock({ isLoading: true }))
     vi.mocked(useNotes).mockReturnValue(createNotesMock({ isLoading: true }))
     vi.mocked(useNotebookChat).mockReturnValue(createChatMock())
 
-    render(<ChatColumn {...mockProps} />)
-    
+    render(<ChatColumn {...baseProps} sourcesLoading={true} />)
+
     // Should show loading spinner
     expect(screen.getByTestId('loading-spinner')).toBeInTheDocument()
   })
 
   it('renders chat panel when data is loaded', () => {
-    vi.mocked(useSources).mockReturnValue(createSourcesMock({ isLoading: false }))
     vi.mocked(useNotes).mockReturnValue(createNotesMock({ isLoading: false }))
     vi.mocked(useNotebookChat).mockReturnValue(createChatMock())
 
-    render(<ChatColumn {...mockProps} />)
-    
+    render(<ChatColumn {...baseProps} sourcesLoading={false} />)
+
     // Should show chat panel
     expect(screen.getByTestId('chat-panel')).toBeInTheDocument()
   })

frontend/src/app/(dashboard)/notebooks/components/ChatColumn.tsx

@@ -2,7 +2,6 @@
 
 import { useMemo } from 'react'
 import { useNotebookChat } from '@/lib/hooks/useNotebookChat'
-import { useSources } from '@/lib/hooks/use-sources'
 import { useNotes } from '@/lib/hooks/use-notes'
 import { ChatPanel } from '@/components/source/ChatPanel'
 import { LoadingSpinner } from '@/components/common/LoadingSpinner'
@@ -10,17 +9,19 @@ import { Card, CardContent } from '@/components/ui/card'
 import { AlertCircle } from 'lucide-react'
 import { ContextSelections } from '../[id]/page'
 import { useTranslation } from '@/lib/hooks/use-translation'
+import { SourceListResponse } from '@/lib/types/api'
 
 interface ChatColumnProps {
   notebookId: string
   contextSelections: ContextSelections
+  sources: SourceListResponse[]
+  sourcesLoading: boolean
 }
 
-export function ChatColumn({ notebookId, contextSelections }: ChatColumnProps) {
+export function ChatColumn({ notebookId, contextSelections, sources, sourcesLoading }: ChatColumnProps) {
   const { t } = useTranslation()
 
-  // Fetch sources and notes for this notebook
-  const { data: sources = [], isLoading: sourcesLoading } = useSources(notebookId)
+  // Fetch notes for this notebook
   const { data: notes = [], isLoading: notesLoading } = useNotes(notebookId)
 
   // Initialize notebook chat hook