[Somya-jain0811]

Fixes #624

Summary

When running the remote wrapper nodes (tools/cwrap.py and tools/pwrap.py) with DEBUG logging enabled, the Mediator API key read from concore.apikey is logged in plaintext, both in the standalone API Key: line and embedded within the logged POST request URLs.

What was done

1. Masking without losing debuggability: Rather than deleting the log lines completely, added mask_apikey(key) to both wrappers. It keeps only the last 4 characters visible (e.g. ******1234) and handles ?apikey= query strings. This prevents credential leaks in log files while still letting developers confirm that the key was detected.
2. Import guard for testability: Wrapped the top-level script logic in def run() guarded by if __name__ == "__main__":. Previously, the file executed polling loops immediately at top level on import, which made it impossible to import into unit tests without triggering network requests or blocking.
3. Unit tests: Added tests/test_wrapper_security.py with 17 tests covering empty/short/normal keys, query string variants, and using pytest's caplog to verify that raw secret strings never enter the logging stream.

Test results

All 17 tests pass cleanly:

tests/test_wrapper_security.py ................. [100%]
17 passed in 0.59s

Ready for review!