fix return-value/deprecated API bugs, accumulation lock leaks, code cleanup

- raise instead of silent None for unsupported operands and empty negation
- validate before acquiring lock in Accumulation operators (no RLock leak)
- Accumulation._copy_provenance helper, ADC_Result._copy_metadata for all result paths
- shared _sandbox_stdout_redirect contextmanager for sandboxed scripts
- TemperatureMonitor dead code removal (gtk helper, traceback, unused properties)
- new unit tests incl. lock-freedom regression test
- gitignore sphinx generated doc/_autosummary/ and doc/damaris/

tests/test_ExperimentHandling.py

@@ -0,0 +1,70 @@
+import sys
+import threading
+import unittest
+
+from damaris.gui.ExperimentHandling import ExperimentHandling
+from damaris.gui.ResultHandling import ResultHandling
+
+
+class _FakeWriter:
+    def __init__(self):
+        self.sent = []
+
+    def send_next(self, job, quit=False):
+        self.sent.append(job)
+
+
+class _FakeResultIterator:
+    def __init__(self):
+        self.quit_flag = threading.Event()
+
+    def __iter__(self):
+        return iter([])
+
+
+class TestSandboxStdoutRestore(unittest.TestCase):
+    """
+    sys.stdout/sys.stderr are process-global: the sandbox redirect in
+    run() must be undone even when the script raises or returns early.
+    """
+
+    def test_experiment_stdout_restored_after_script_exception(self):
+        orig_stdout = sys.stdout
+        orig_stderr = sys.stderr
+        handled = ExperimentHandling("raise ValueError('boom')", None, None,
+                                     log_callback=lambda line: None)
+        handled.run()
+        self.assertIs(sys.stdout, orig_stdout)
+        self.assertIs(sys.stderr, orig_stderr)
+        self.assertIsNotNone(handled.raised_exception)
+
+    def test_experiment_stdout_restored_on_success(self):
+        orig_stdout = sys.stdout
+        writer = _FakeWriter()
+        handled = ExperimentHandling("print('hello')\nexperiment = lambda: iter([])",
+                                     writer, None, log_callback=lambda line: None)
+        handled.run()
+        self.assertIs(sys.stdout, orig_stdout)
+        self.assertIsNone(handled.raised_exception)
+
+    def test_result_stdout_restored_after_script_exception(self):
+        orig_stdout = sys.stdout
+        orig_stderr = sys.stderr
+        handling = ResultHandling("raise ValueError('boom')", _FakeResultIterator(),
+                                  None, log_callback=lambda line: None)
+        handling.run()
+        self.assertIs(sys.stdout, orig_stdout)
+        self.assertIs(sys.stderr, orig_stderr)
+        self.assertIsNotNone(handling.raised_exception)
+
+    def test_result_stdout_restored_without_result_function(self):
+        orig_stdout = sys.stdout
+        handling = ResultHandling("x = 1", _FakeResultIterator(), None,
+                                  log_callback=lambda line: None)
+        handling.run()
+        self.assertIs(sys.stdout, orig_stdout)
+        self.assertIsNone(handling.raised_exception)
+
+
+if __name__ == "__main__":
+    unittest.main()