feat(api): завершение миграции на Fastify — sync, scheduler, backup

Портированы BILLmanager sync/test/balance, планировщик и Telegram,
импорт/экспорт бэкапов и migrate API; Docker по умолчанию на fastify.
Добавлен .understand-anything/ в gitignore, исправлен path codegraph в MCP.

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

.gitignore

@@ -18,6 +18,9 @@ dist-ssr
 coverage
 *.tsbuildinfo
 
+# Understand Anything (knowledge graph)
+.understand-anything/
+
 # Editor directories and files
 .vscode/*
 !.vscode/extensions.json