fix: avoid history reclamation during structure-only upgrades

Ordinary database schema upgrades previously ran VACUUM on free pages and
showed misleading history-cleanup progress. Separate structure upgrades from
required legacy conversions, retaining reclamation intent only for retries
within the same startup. Preserve released data without new schema versions
or persistent migration markers; Agent and normal writes remain unchanged.

Add real SQLite and Worker regressions, bilingual operation-specific startup
copy, and migration documentation. Synchronize native Electron drag input
with actual resize state without weakening layout assertions.

Validation: 47 focused migration tests passed; typecheck, lint and diff checks
passed. Final full suite: 5137 passed, 74 skipped, 2 unrelated Electron failures.
Both failing Electron tests passed an isolated rerun; full CI remains unverified.

Release note: 修复普通数据库结构升级再次整理历史和回收空间的问题；仅在需要转换旧数据时执行相关处理，启动页准确显示当前升级操作。

src/main/assistant/activity-history-io.test.ts

@@ -6,7 +6,7 @@ import { join } from 'node:path'
 import { DatabaseSync } from 'node:sqlite'
 import { expect, it, vi } from 'vitest'
 import { AssistantDatabase } from './assistant-database'
-import { upgradeAssistantStorage } from './assistant-storage-upgrade'
+import { getPendingAssistantStorageUpgrade, upgradeAssistantStorage } from './assistant-storage-upgrade'
 
 it('migrates activity history and writes only changed records during streaming', () => {
   const directory = mkdtempSync(join(tmpdir(), 'goodbuddy-save-io-'))
@@ -41,6 +41,7 @@ it('migrates activity history and writes only changed records during streaming',
     }
     const beforeBytes = statSync(`${path}-wal`).size
     database.close()
+    expect(getPendingAssistantStorageUpgrade(path)).toEqual({ migrateNotes: false, reclaimSpace: true })
     upgradeAssistantStorage(path, () => undefined)
     database.initialize(directory)
     expect(database.getActivityHistory()).toEqual({ records, legacyHistoryMayBeIncomplete: true })