Summary

• skip ancestor PIDs while scanning the process table for running gateways
• keep PID-file and service-managed discovery unchanged
• add a regression test covering an interactive CLI parent plus a real gateway child

Root cause

find_gateway_pids() scans process-table matches broadly enough to see the foreground CLI process that launched hermes gateway run --replace. Because the scan only excluded the current PID, an ancestor in the same process tree could still be reported as an already-running gateway.

Fix

Restrict the ancestor filter to _scan_gateway_pids() so only process-table matches are skipped when they belong to the current process tree. This preserves the existing PID-file fallback and service PID discovery paths.

Regression coverage

• added TestFindGatewayPidsExclude::test_excludes_ancestor_process_tree
• verifies a matching CLI ancestor is ignored while a real gateway/run.py process is still returned

Testing

• scripts/run_tests.sh tests/hermes_cli/test_update_gateway_restart.py::TestFindGatewayPidsExclude::test_excludes_ancestor_process_tree
• scripts/run_tests.sh tests/hermes_cli/test_update_gateway_restart.py
• scripts/run_tests.sh tests/hermes_cli/test_gateway.py

Closes #13242