Verifies the watcher fix end-to-end: every passing tool used to
return the same execute_on_primary_thread marshal error and now
runs cleanly. Documents 5 unrelated pre-existing upstream bugs
exposed by the test (create_folder keyword mismatch, JSON long
serialisation in compile_project / get_compile_messages, online
API drift in connect/download/write_variable, orphaned CODESYS
on shutdown_codesys, library list/add inconsistency).
Test ran on SP21 Patch 5 due to MCP child orphaning during
re-registration churn; same architecture means SP22 is expected
to behave identically.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
a9347f7677