Leaving a block deletes the sandbox it made

From the next release of the TypeScript and Python SDKs, the end of an await using or with block deletes a sandbox that Sandbox.create() made there, where it used to stop it and keep its disk, which bills. Create it with keep: true (Python keep=True) to stop it instead, as before. A sandbox the block got with get(), or one getOrCreate() found already there, is still only stopped. The drop-ins keep each rival's own block exit: withruntime/e2b (Python) kills, withruntime/vercel stops in TypeScript and deletes in Python.