feat(w4): ship v1.5.0 timeline, character arc, and compliance

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main/ipc/handlers/arc.handler.ts

@@ -0,0 +1,13 @@
+import { ipcMain } from 'electron'
+import { IPC } from '../../../shared/ipc-channels'
+import { ArcService } from '../../services/arc.service'
+import type { BookRegistryService } from '../../services/book-registry'
+import { wrap } from '../result'
+
+export function registerArcHandlers(registry: BookRegistryService): void {
+  ipcMain.handle(
+    IPC.ARC_GET_FOR_CHARACTER,
+    (_e, { bookId, settingId }: { bookId: string; settingId: string }) =>
+      wrap(() => new ArcService(registry.getDb(bookId)).getForCharacter(settingId))
+  )
+}