[Feature]: Support Variable Interpolation in env: configuration

[Bihan]

Problem

Currently the env: configuration does not support variable interpolation. This means that when we define environment variables like:

env:
  - NUM_SHARD=$DSTACK_GPUS_NUM

The value is not evaluated at runtime. This limitation makes it difficult to define dynamic environment configurations.

Solution

No response

Workaround

No response

Would you like to help us implement this feature by sending a PR?

No