feat: ship v1.2.0 Wave 1 foundation with book settings, chapter management, and focus mode

Deliver schema v9, book/chapter IPC extensions, BookSettingsTab, chapter meta/tags,
AI session menu, focus mode and TTS, template context enrich, and Wave 1 E2E coverage.

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

src/shared/electron-api.d.ts

@@ -32,6 +32,8 @@ import type {
   Snapshot,
   SnapshotType,
   UpdateChapterParams,
+  UpdateBookMetaParams,
+  ChapterTag,
   Volume,
   WordFreqResult,
   KnowledgeEntry,
@@ -73,10 +75,12 @@ export interface ElectronAPI {
     create: (params: CreateBookParams) => Promise<IpcResult<BookMeta>>
     delete: (bookId: string) => Promise<IpcResult<void>>
     open: (bookId: string) => Promise<IpcResult<BookOpenResult>>
-    updateMeta: (
-      bookId: string,
-      patch: { lastChapterId?: string | null; status?: BookMeta['status'] }
-    ) => Promise<IpcResult<BookMeta>>
+    updateMeta: (bookId: string, patch: UpdateBookMetaParams) => Promise<IpcResult<BookMeta>>
+    pickCover: (bookId: string) => Promise<IpcResult<BookMeta | null>>
+  }
+  bookPrefs: {
+    get: (bookId: string, key: string) => Promise<IpcResult<string | null>>
+    set: (bookId: string, key: string, value: string) => Promise<IpcResult<void>>
   }
   volume: {
     create: (bookId: string, name: string) => Promise<IpcResult<Volume>>
@@ -105,6 +109,11 @@ export interface ElectronAPI {
       publishStatus: PublishStatus
     ) => Promise<IpcResult<Chapter>>
   }
+  chapterTag: {
+    list: (bookId: string, chapterId: string) => Promise<IpcResult<ChapterTag[]>>
+    set: (bookId: string, chapterId: string, tag: string, color?: string) => Promise<IpcResult<void>>
+    remove: (bookId: string, chapterId: string, tag: string) => Promise<IpcResult<void>>
+  }
   outline: {
     list: (bookId: string) => Promise<IpcResult<OutlineItem[]>>
     create: (
@@ -221,6 +230,11 @@ export interface ElectronAPI {
       patch: Partial<{ title: string; model: string; archived: boolean; context: AiContextBinding }>
     ) => Promise<IpcResult<AiSession>>
     sessionDelete: (bookId: string, sessionId: string) => Promise<IpcResult<void>>
+    sessionExport: (
+      bookId: string,
+      sessionId: string,
+      format?: 'markdown' | 'txt'
+    ) => Promise<IpcResult<string | null>>
     messageList: (bookId: string, sessionId: string) => Promise<IpcResult<AiMessage[]>>
     chat: (
       bookId: string,