feat: add environment variable support for python_repl directory

[yakatak5]

Description

Updating python_repl tool to check for state file directory path via environment variable: PYTHON_REPL_PERSISTENCE_DIR

As well as additional security and validation measures to ensure safe directory path referenced

Related Issues

#311

Documentation PR

Type of Change

Other (please describe): Tool Feature

Testing

Created and ran unit tests

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[awsarron]

Thanks @yakatak5! One minor comment

[awsarron]

One more thing - linter failed with:

Run hatch run test-lint
Creating environment: default
Installing project in development mode
Checking dependencies
Creating environment: hatch-static-analysis
Checking dependencies
Syncing dependencies
tests/test_python_repl.py:3:1: I001 [*] Import block is un-sorted or un-formatted
Found 1 error.
[*] 1 fixable with the `--fix` option.
Error: Process completed with exit code 1.

[awsarron]

Minor nit on the README update