refactor: extract hooks and components from NoteListInner for code health

Split NoteListInner (190 lines, 14 props) into focused units:
- useNoteListSort: sort state, migration, type frontmatter persistence
- useNoteListSearch: search/query state and toggle
- useMultiSelectKeyboard: keyboard shortcuts for bulk actions
- useModifiedFilesState: modified file tracking and status resolution
- NoteListHeader: 52px header bar with sort, search, and create

Also extracted pure helpers (handleEscapeKey, handleSelectAllKey,
handleBulkActionKey, resolveEmptyText, deriveEffectiveSort, etc.)
to reduce cyclomatic complexity in remaining functions.

NoteListInner body: 190 → 48 lines. CodeScene health: 8.54 → 9.36.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/useNoteListSort.test.tsx

@@ -0,0 +1,151 @@
+import { render, screen } from '@testing-library/react'
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+import { NoteList } from './NoteList'
+import type { VaultEntry, SidebarSelection } from '../types'
+
+const localStorageMock = (() => {
+  let store: Record<string, string> = {}
+  return {
+    getItem: vi.fn((key: string) => store[key] ?? null),
+    setItem: vi.fn((key: string, value: string) => { store[key] = value }),
+    removeItem: vi.fn((key: string) => { delete store[key] }),
+    clear: vi.fn(() => { store = {} }),
+  }
+})()
+Object.defineProperty(globalThis, 'localStorage', { value: localStorageMock, writable: true })
+
+function makeEntry(overrides: Partial<VaultEntry> = {}): VaultEntry {
+  return {
+    path: '/test/note.md', filename: 'note.md', title: 'Test Note',
+    isA: 'Note', aliases: [], belongsTo: [], relatedTo: [],
+    status: null, owner: null, cadence: null, archived: false,
+    trashed: false, trashedAt: null, modifiedAt: 1700000000,
+    createdAt: null, fileSize: 100, snippet: '', wordCount: 0,
+    relationships: {}, icon: null, color: null, order: null,
+    sidebarLabel: null, template: null, sort: null,
+    outgoingLinks: [], properties: {},
+    ...overrides,
+  }
+}
+
+const noop = vi.fn()
+
+function renderNoteList(props: {
+  entries: VaultEntry[]
+  selection: SidebarSelection
+  onUpdateTypeSort?: (path: string, key: string, value: string | number | boolean | string[] | null) => void
+  updateEntry?: (path: string, patch: Partial<VaultEntry>) => void
+}) {
+  return render(
+    <NoteList
+      entries={props.entries}
+      selection={props.selection}
+      selectedNote={null}
+      allContent={{}}
+      onSelectNote={noop}
+      onReplaceActiveTab={noop}
+      onCreateNote={noop}
+      onUpdateTypeSort={props.onUpdateTypeSort}
+      updateEntry={props.updateEntry}
+    />,
+  )
+}
+
+beforeEach(() => { localStorageMock.clear() })
+
+describe('useNoteListSort (via NoteList)', () => {
+  it('renders notes sorted by modified date by default', () => {
+    const entries = [
+      makeEntry({ path: '/a.md', title: 'Alpha', modifiedAt: 1000 }),
+      makeEntry({ path: '/b.md', title: 'Beta', modifiedAt: 3000 }),
+      makeEntry({ path: '/c.md', title: 'Charlie', modifiedAt: 2000 }),
+    ]
+    renderNoteList({ entries, selection: { kind: 'filter', filter: 'all' } })
+    const items = screen.getAllByText(/Alpha|Beta|Charlie/)
+    expect(items[0].textContent).toBe('Beta')
+    expect(items[1].textContent).toBe('Charlie')
+    expect(items[2].textContent).toBe('Alpha')
+  })
+
+  it('reads sort from type document for sectionGroup selection', () => {
+    const typeDoc = makeEntry({ path: '/type/note.md', title: 'Note', isA: 'Type', sort: 'title:asc' })
+    const entries = [
+      typeDoc,
+      makeEntry({ path: '/c.md', title: 'Charlie', modifiedAt: 3000 }),
+      makeEntry({ path: '/a.md', title: 'Alpha', modifiedAt: 1000 }),
+      makeEntry({ path: '/b.md', title: 'Beta', modifiedAt: 2000 }),
+    ]
+    renderNoteList({ entries, selection: { kind: 'sectionGroup', type: 'Note', label: 'Notes' } })
+    const items = screen.getAllByText(/Alpha|Beta|Charlie/)
+    expect(items[0].textContent).toBe('Alpha')
+    expect(items[1].textContent).toBe('Beta')
+    expect(items[2].textContent).toBe('Charlie')
+  })
+
+  it('shows type title as header for sectionGroup selection', () => {
+    const typeDoc = makeEntry({ path: '/type/project.md', title: 'Project', isA: 'Type' })
+    renderNoteList({ entries: [typeDoc], selection: { kind: 'sectionGroup', type: 'Project', label: 'Projects' } })
+    expect(screen.getByText('Project')).toBeInTheDocument()
+  })
+
+  it('migrates localStorage sort to type frontmatter when type has no sort', () => {
+    localStorageMock.setItem('laputa-sort-preferences', JSON.stringify({ '__list__': { option: 'title', direction: 'asc' } }))
+    const onUpdateTypeSort = vi.fn()
+    const updateEntry = vi.fn()
+    const typeDoc = makeEntry({ path: '/type/project.md', title: 'Project', isA: 'Type', sort: null })
+    const entries = [typeDoc, makeEntry()]
+
+    renderNoteList({
+      entries,
+      selection: { kind: 'sectionGroup', type: 'Project', label: 'Projects' },
+      onUpdateTypeSort,
+      updateEntry,
+    })
+
+    expect(onUpdateTypeSort).toHaveBeenCalledWith('/type/project.md', 'sort', 'title:asc')
+    expect(updateEntry).toHaveBeenCalledWith('/type/project.md', { sort: 'title:asc' })
+  })
+
+  it('does not migrate if type already has sort', () => {
+    localStorageMock.setItem('laputa-sort-preferences', JSON.stringify({ '__list__': { option: 'title', direction: 'asc' } }))
+    const onUpdateTypeSort = vi.fn()
+    const updateEntry = vi.fn()
+    const typeDoc = makeEntry({ path: '/type/project.md', title: 'Project', isA: 'Type', sort: 'modified:desc' })
+    const entries = [typeDoc, makeEntry()]
+
+    renderNoteList({
+      entries,
+      selection: { kind: 'sectionGroup', type: 'Project', label: 'Projects' },
+      onUpdateTypeSort,
+      updateEntry,
+    })
+
+    expect(onUpdateTypeSort).not.toHaveBeenCalled()
+  })
+
+  it('falls back to modified when property sort references missing property', () => {
+    localStorageMock.setItem('laputa-sort-preferences', JSON.stringify({ '__list__': { option: 'property:priority', direction: 'asc' } }))
+    const entries = [
+      makeEntry({ path: '/a.md', title: 'Alpha', modifiedAt: 1000, properties: {} }),
+      makeEntry({ path: '/b.md', title: 'Beta', modifiedAt: 3000, properties: {} }),
+    ]
+    renderNoteList({ entries, selection: { kind: 'filter', filter: 'all' } })
+    const items = screen.getAllByText(/Alpha|Beta/)
+    // Should be sorted by modified desc (fallback), so Beta first
+    expect(items[0].textContent).toBe('Beta')
+    expect(items[1].textContent).toBe('Alpha')
+  })
+
+  it('uses property sort when property exists in entries', () => {
+    localStorageMock.setItem('laputa-sort-preferences', JSON.stringify({ '__list__': { option: 'property:priority', direction: 'asc' } }))
+    const entries = [
+      makeEntry({ path: '/b.md', title: 'Beta', modifiedAt: 3000, properties: { priority: 2 } }),
+      makeEntry({ path: '/a.md', title: 'Alpha', modifiedAt: 1000, properties: { priority: 1 } }),
+    ]
+    renderNoteList({ entries, selection: { kind: 'filter', filter: 'all' } })
+    const items = screen.getAllByText(/Alpha|Beta/)
+    // Should be sorted by priority asc: Alpha (1) first, then Beta (2)
+    expect(items[0].textContent).toBe('Alpha')
+    expect(items[1].textContent).toBe('Beta')
+  })
+})