Close the --report-jsonl file when the session ends

pytest_configure opens it and nothing ever closed it; it was left to interpreter
shutdown. Nothing is lost today, because every record is flush()ed as it is
written — which is exactly what makes this worth fixing rather than shrugging
at. The flush is per test phase on a file that gets thousands of them, so it is
the obvious thing for someone to remove when this run feels slow, and the day
that happens the last records of a run vanish with no error and the dashboard
quietly under-reports.

Noticed reviewing #120; not caused by it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: gaurav

tests/conftest.py

@@ -130,6 +130,17 @@ def pytest_runtest_logreport(report):
     _report_file.flush()
 
 
+def pytest_unconfigure(config):
+    # Closed explicitly rather than left to interpreter shutdown. Every line is
+    # flushed as it is written, so nothing is lost today — but that makes this a
+    # bug that only appears if someone ever drops the flush() for speed, which is
+    # the obvious optimisation to reach for on a file written once per test phase.
+    global _report_file
+    if _report_file is not None:
+        _report_file.close()
+        _report_file = None
+
+
 def pytest_addoption(parser):
     # The target environment(s) to target.
     parser.addoption(