test: extend evil test suite

[crepererum]

For #16.

[Copilot]

Pull Request Overview

This PR extends the "evil" test suite to include comprehensive tests for filesystem operations and environment variable access within WASM components. The evil test suite is designed to verify security boundaries and proper sandboxing of WASM execution.

Key changes:

• Added environment variable tests to verify sandbox isolation (env.rs modules)
• Added comprehensive filesystem operation tests covering read/write/permissions (fs.rs modules)
• Extended root filesystem tests with invalid TAR entries, non-TAR content, and unsupported entry types

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
host/tests/integration_tests/evil/test_utils.rs	Added try_scalar_udfs_with_env helper to support passing environment variables to evil tests
host/tests/integration_tests/evil/env.rs	New test module verifying environment variable access (args, current_dir, current_exe, env vars)
host/tests/integration_tests/evil/fs.rs	New test module with comprehensive filesystem operation tests (1065 lines)
host/tests/integration_tests/evil/root.rs	Added tests for invalid TAR entries, non-TAR content, and unsupported entry types
host/tests/integration_tests/evil/mod.rs	Registered new test modules
host/tests/integration_tests/python/runtime/env.rs	Updated to handle empty environment variables correctly
guests/evil/src/env.rs	New guest-side implementation of environment variable access UDFs
guests/evil/src/fs.rs	New guest-side implementation of filesystem operation UDFs
guests/evil/src/root/invalid_entry.rs	New evil payload with invalid TAR entry
guests/evil/src/root/not_tar.rs	New evil payload returning non-TAR bytes
guests/evil/src/root/unsupported_entry.rs	New evil payload with unsupported TAR entry type
guests/evil/src/root/many_files.rs	Updated to accept configurable limit via environment variable
guests/evil/src/root/mod.rs	Registered new root payload modules
guests/evil/src/lib.rs	Updated multiplexer to route to new evil payloads

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[mhilton]

Seeing "UDF" vs "Udf" is a little jarring.

[crepererum]

Fair, I'll fix that repo-wide in a follow-up PR.