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_email_targeted_edit_scope.py

@@ -0,0 +1,26 @@
+from types import SimpleNamespace
+
+import pytest
+
+from src.clean_agent_preview import active_editor_whole_draft_request
+
+
+@pytest.mark.parametrize('prompt', [
+    'Change Tuesday to Wednesday only in my reply, not in the quoted email.',
+    'Fix the spelling in this draft.',
+    'Remove the last sentence from my reply.',
+    'Replace "draft" with "final" in the subject.',
+    'Do not write another reply. Correct the date only.',
+])
+def test_targeted_email_edit_does_not_force_whole_body_replacement(prompt):
+    document = SimpleNamespace(title='Fixture', language='email', current_content='Existing reply')
+    assert not active_editor_whole_draft_request(document, prompt)
+
+
+@pytest.mark.parametrize('prompt', [
+    'Write reply this email', 'Draft a reply', 'Please respond to this email.',
+    'Could you write a reply saying I can attend?', 'Reply politely declining.',
+])
+def test_composition_command_still_selects_whole_draft_writer(prompt):
+    document = SimpleNamespace(title='Fixture', language='email', current_content='Existing reply')
+    assert active_editor_whole_draft_request(document, prompt)