## Summary
Instead of throwing an error at server startup when LOCAL code
interpreter is configured in production, we now return a DisabledDriver
that only throws when the code interpreter is actually used.
## Changes
- Created `DisabledDriver` class that implements `CodeInterpreterDriver`
but throws an error only when `execute()` is called
- Added `DISABLED` to the `CodeInterpreterDriverType` enum
- Updated the factory to return a `DISABLED` driver config instead of
throwing when LOCAL is used in production
- Updated the module to handle the new `DISABLED` driver type
## Motivation
Many users don't need the code interpreter feature and want to deploy to
production without configuring E2B. Previously, the server would crash
at startup if `CODE_INTERPRETER_TYPE=LOCAL` was set in production.
**Before:** Server crashes at startup in production if
`CODE_INTERPRETER_TYPE=LOCAL`
**After:** Server starts fine. The error only occurs if someone actually
tries to **use** the code interpreter feature, at which point they get a
clear error message explaining how to configure E2B.
