feat(w3): add continuous read mode and Wave 3 plan

Introduce ReadModeOverlay with device width and font theme persistence, sidebar and volume menu entry, plus E2E-READ-01 through 03.

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

src/renderer/stores/useReadModeStore.ts

@@ -0,0 +1,24 @@
+import { create } from 'zustand'
+import type { GlobalSettings } from '@shared/types'
+
+export type ReadDeviceWidth = NonNullable<GlobalSettings['readModeDeviceWidth']>
+export type ReadFontTheme = NonNullable<GlobalSettings['readModeFontTheme']>
+
+interface ReadModeState {
+  open: boolean
+  volumeId: string | null
+  chapterIndex: number
+  openForVolume: (volumeId: string, chapterIndex?: number) => void
+  close: () => void
+  setChapterIndex: (index: number) => void
+}
+
+export const useReadModeStore = create<ReadModeState>((set) => ({
+  open: false,
+  volumeId: null,
+  chapterIndex: 0,
+  openForVolume: (volumeId, chapterIndex = 0) =>
+    set({ open: true, volumeId, chapterIndex: Math.max(0, chapterIndex) }),
+  close: () => set({ open: false, volumeId: null, chapterIndex: 0 }),
+  setChapterIndex: (chapterIndex) => set({ chapterIndex: Math.max(0, chapterIndex) })
+}))

src/renderer/stores/useSettingsStore.ts

@@ -32,6 +32,9 @@ export const useSettingsStore = create<SettingsState>((set, get) => ({
   chapterTemplates: [],
   submissionPresets: [],
   defaultSubmissionPresetId: 'builtin-webnovel',
+  readModeFontTheme: 'serif',
+  readModeDeviceWidth: 'desktop',
+  enableFocusAmbientSound: false,
   loaded: false,
   load: async () => {
     const data = await ipcCall(() => window.electronAPI.settings.get())