get_due_jobs() called load_jobs() and save_jobs() without holding
_jobs_file_lock, creating a race with the locked mark_job_run() and
advance_next_run(). Wrap get_due_jobs() with the lock (delegating to a
new _get_due_jobs_locked() inner function) so all load→modify→save
cycles are serialised. Add two regression tests: one verifying 3
concurrent mark_job_run() calls each land their correct last_status and
last_run_at without overwrites, and a stress test confirming 10 parallel
calls each increment their job's completed count to exactly 1.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Set max_result_size_chars=100_000 on the read_file registry entry (was
float('inf')), closing the Layer 2 defense-in-depth gap in
tool_result_storage.py. The existing Layer 1 guard inside
_handle_read_file already returns a JSON error for oversized reads;
this aligns the registry cap with every other tool.
Update test_read_file_never_persisted → test_read_file_result_size_cap
to assert 100_000, and add test_read_file_registry_cap_is_100k as an
explicit regression guard against re-introducing float('inf').
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
