Preserve preview harness, editor, email and task improvements

Snapshot current maintainer-preview application changes and regression fixtures for integration into lab. Excludes local runtime data, evaluation outputs and source backups. Focused Python regression selection: 140 passed; full suite not certified.

tests/test_calendar_retiming_routing.py

@@ -0,0 +1,28 @@
+import pytest
+
+from src.turn_contract import requested_capabilities
+from src.clean_agent_preview import requests_mutation
+
+
+@pytest.mark.parametrize('prompt', [
+    'Push that event back by two hours.',
+    'Please bring the meeting forward by 30 minutes.',
+    'Could you postpone my appointment until Friday?',
+    'Delay the event by one day.',
+    'Shift the meeting to 16:00 UTC.',
+])
+def test_temporal_rescheduling_is_calendar_action(prompt):
+    assert requested_capabilities(prompt) == {'calendar'}
+    assert requests_mutation(prompt)
+
+
+@pytest.mark.parametrize('prompt', [
+    'Do not push that event back by two hours.',
+    'Why did they postpone my appointment until Friday?',
+    'Explain how to bring the meeting forward by 30 minutes.',
+    'The event was delayed by one day.',
+    'Push the code to the remote repository.',
+])
+def test_temporal_discussion_does_not_authorize_calendar_write(prompt):
+    from src.turn_contract import calendar_retiming_request
+    assert not calendar_retiming_request(prompt)