Persist profile state in SQLite with background writes (#22612)

Migrate profile state to SQLite and move writes and backups into a background worker. Acknowledge terminal, SSH and automation changes only after durable saves. Preserve JSON import, recovery, rollback and compatibility exports.

Validate migration, worker failures, maintenance, cross-profile moves and terminal lifetime races with unit, integration and end-to-end coverage.

src/main/sqlite/sync-database.ts

@@ -1,5 +1,5 @@
 import { existsSync } from 'node:fs'
-import type { DatabaseSync, StatementSync, SQLInputValue } from 'node:sqlite'
+import type { backup, BackupOptions, DatabaseSync, StatementSync, SQLInputValue } from 'node:sqlite'
 
 type SqlitePath = ConstructorParameters<typeof DatabaseSync>[0]
 
@@ -36,6 +36,15 @@ function loadDatabaseSync(): typeof DatabaseSync {
     .DatabaseSync
 }
 
+function hasBackup(value: unknown): value is { backup: typeof backup } {
+  return (
+    typeof value === 'object' &&
+    value !== null &&
+    'backup' in value &&
+    typeof value.backup === 'function'
+  )
+}
+
 class SyncDatabase {
   private readonly db: DatabaseSync
   private readonly statementCache = new Map<string, StatementSync>()
@@ -100,6 +109,21 @@ class SyncDatabase {
     return this.db.isTransaction
   }
 
+  /** The source connection must remain open until the native backup settles. */
+  async backup(path: string, options?: BackupOptions): Promise<number> {
+    const sqlite: unknown =
+      typeof process.getBuiltinModule === 'function'
+        ? process.getBuiltinModule('node:sqlite')
+        : undefined
+    if (!hasBackup(sqlite)) {
+      throw new Error('Asynchronous SQLite backup is unavailable in this Node.js runtime')
+    }
+    if (this.db.isTransaction) {
+      throw new Error('Asynchronous SQLite backup requires an idle database connection')
+    }
+    return sqlite.backup(this.db, path, options ?? {})
+  }
+
   close(): void {
     this.statementCache.clear()
     this.db.close()