Improve development environment setup instructions

[ashum9]

Problem

While setting up the neural-lam development environment locally, I ran
into dependency compatibility issues that caused the test suite to fail.

In particular:

• xarray <= 2025.4.0 caused failures with zarr v3 datastores
• dependency versions required for a working development environment
  are not clearly documented

Although these issues can be resolved, the setup process can be confusing
for new contributors.

Proposal

Add a short "Development Environment" section to the README that includes:

• Instructions for creating a virtual environment
• Installing neural-lam in editable mode
• Running the test suite
• Example of a working dependency configuration

This would make it easier for new contributors to set up the project and
start contributing.

Context

I recently set up the development environment and ran the full test suite
successfully:

pytest
110 passed, 0 failed

I would be happy to work on improving the documentation if this approach
sounds reasonable.

[ashum9]

@observingClouds sir kindly review this issue , thankyou .

[sadamov]

Closing as the development environment setup is being covered by the CONTRIBUTING.md from #407 (approved, awaiting merge). The original framing of adding venv instructions to the README was rejected per the discussion.