feat: ship v0.8.0 with writing logs and AI knowledge extraction

Deliver P5.2 writing day logs, cockpit heatmap, streak tracking, and chapter knowledge auto-extraction with merge review.

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

src/main/db/repositories/chapter-writing-snapshot.repo.ts

@@ -0,0 +1,35 @@
+import type { SqliteDb } from '../types'
+
+export interface ChapterWritingSnapshot {
+  loggedWordCount: number
+  finishSupplemented: boolean
+}
+
+export class ChapterWritingSnapshotRepository {
+  constructor(private db: SqliteDb) {}
+
+  get(chapterId: string): ChapterWritingSnapshot | null {
+    const row = this.db
+      .prepare(
+        'SELECT logged_word_count, finish_supplemented FROM chapter_writing_snapshots WHERE chapter_id = ?'
+      )
+      .get(chapterId) as { logged_word_count: number; finish_supplemented: number } | undefined
+    if (!row) return null
+    return {
+      loggedWordCount: row.logged_word_count,
+      finishSupplemented: row.finish_supplemented === 1
+    }
+  }
+
+  upsert(chapterId: string, loggedWordCount: number, finishSupplemented = false): void {
+    this.db
+      .prepare(
+        `INSERT INTO chapter_writing_snapshots (chapter_id, logged_word_count, finish_supplemented)
+         VALUES (?, ?, ?)
+         ON CONFLICT(chapter_id) DO UPDATE SET
+           logged_word_count = excluded.logged_word_count,
+           finish_supplemented = excluded.finish_supplemented`
+      )
+      .run(chapterId, loggedWordCount, finishSupplemented ? 1 : 0)
+  }
+}