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_search_folder_contract.py

@@ -0,0 +1,29 @@
+import pytest
+
+from mcp_servers import email_server
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize('scope,expected', [
+    ({'folder': 'Archive'}, ['Archive']),
+    ({'folder': 'Finance/2026'}, ['Finance/2026']),
+    ({'folders': ['INBOX', 'Sent']}, ['INBOX', 'Sent']),
+    ({'folders': ['Sent'], 'folder': 'Archive'}, ['Sent']),
+    ({}, None),
+])
+async def test_search_honors_advertised_folder(monkeypatch, scope, expected):
+    calls = []
+    monkeypatch.setattr(email_server, '_read_accounts_from_db', lambda: [])
+    monkeypatch.setattr(email_server, '_mcp_owner_required', lambda accounts: False)
+
+    def search(query, **kwargs):
+        calls.append((query, kwargs))
+        return []
+
+    monkeypatch.setattr(email_server, '_search_emails', search)
+    await email_server.call_tool('search_emails', {
+        'query': 'design review', 'account': 'fixture@example.com', **scope,
+    })
+    assert len(calls) == 1
+    assert calls[0][1]['folders'] == expected
+    assert calls[0][1]['account'] == 'fixture@example.com'