feat: ship v0.6.0 with cockpit, knowledge base, and chapter bridge

Deliver P5 writer workflow: writing cockpit, manual knowledge CRUD with review, chapter bridge with optional AI, publish status, and stock buffer reminders.

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

src/main/db/repositories/book-prefs.repo.ts

@@ -0,0 +1,21 @@
+import type { SqliteDb } from '../types'
+
+export class BookPrefsRepository {
+  constructor(private db: SqliteDb) {}
+
+  get(key: string): string | null {
+    const row = this.db.prepare('SELECT value FROM book_preferences WHERE key = ?').get(key) as
+      | { value: string }
+      | undefined
+    return row?.value ?? null
+  }
+
+  set(key: string, value: string): void {
+    this.db
+      .prepare(
+        `INSERT INTO book_preferences (key, value) VALUES (?, ?)
+         ON CONFLICT(key) DO UPDATE SET value = excluded.value`
+      )
+      .run(key, value)
+  }
+}