next.js

04a08435 - Remove LMDB backend and ReadTransaction abstractions from turbo-tasks-backend (#91284)

Remove LMDB backend and ReadTransaction abstractions from turbo-tasks-backend (#91284) ## Summary Remove the unused LMDB database backend and the `ReadTransaction` abstraction layer from `turbo-tasks-backend`. This is a pure cleanup that deletes ~1,500 lines of code and eliminates all `unsafe` blocks related to transaction lifetime management. **Motivation:** - This was much more useful in the early days of the persistence layer where comparing against a 'known good' db was useful, but this has rotted and turbo-persistence has gained lots of tests and usage so that this is not needed. - Carrying the code added a lot of complexity to APIs e.g. - The `ReadTransaction` abstraction existed solely to support LMDB's transaction-based read model - The only remaining backend (`TurboKeyValueDatabase` via `turbo-persistence`) already used `()` as its `ReadTransaction` type, making the entire abstraction dead weight - The transaction plumbing required `unsafe` transmute-based lifetime extension in `ExecuteContextImpl`, adding complexity and risk for no benefit - The WriteBatch::Serial branches complicated already subtle code paths