fix(harness): ship coherent vendor harness cluster

Rebuild PR C to ship the vendor/photocraft harness as a coherent unit
(vendor implementation + vendor tests) instead of a per-file ahead/behind
mix that produced broken imports and 6+ test failures.

- Flip 36 harness impl/route/test files back to vendor (the per-file
  line-set policy misclassified user-rewritten files as 'behind').
- Flip core/models.py + src/tool_approval_scopes.py to vendor: vendor's
  harness (authority.py, turn_contract.py, clean_agent_preview.py) depends
  on vendor's older approval-scope API; upstream added
  CHAT_SESSION_APPROVAL_SIGNATURE_FIELD that vendor's core/models.py lacks.
- Add src/shutdown.py (new vendor infra) required by routes/chat_routes.py.
- Keep src/agent_tools/__init__.py at upstream (editor_tools registration
  lives in PR B).

Upstream-only security divergence preserved in C_upstream_delta.patch and
flagged for integration-time reconciliation.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_calendar_reminder_minutes_parsing.py

@@ -49,6 +49,9 @@ async def _create_with_reminder(reminder, owner):
 
 
 @pytest.mark.parametrize("reminder,expected", [
+    (0, 0),              # At-event reminder must not compare equal to False.
+    (0.0, 0),
+    ("0", 0),
     ("5 mins", 5),
     ("10 mins", 10),
     ("2 hrs", 120),
@@ -91,6 +94,15 @@ async def test_no_reminder_when_offset_absent():
     assert "reminder set" not in res.get("response", ""), res
 
 
+@pytest.mark.parametrize("reminder", [False, "off", "false", None])
+async def test_disabled_reminder_is_distinct_from_zero(reminder):
+    owner = "tester-" + uuid.uuid4().hex[:6]
+    res = await _create_with_reminder(reminder, owner)
+    assert res.get("exit_code") == 0, res
+    assert not res.get("has_reminder"), res
+    assert res.get("reminder_note_id") is None, res
+
+
 async def test_update_event_can_add_reminder_after_creation():
     owner = "tester-" + uuid.uuid4().hex[:6]
     from src.tool_implementations import do_manage_calendar
@@ -123,37 +135,3 @@ async def test_update_event_can_add_reminder_after_creation():
         assert note is not None, "update_event should create the reminder note"
     finally:
         db.close()
-
-
-async def test_reminder_and_duration_parsers_stay_linear_on_digit_and_space_floods():
-    """CodeQL py/polynomial-redos: `(\\d+)\\s*unit` rescanned a digit run from
-    every offset and `alarm\\s*:?\\s*\\d+` split one whitespace run two ways.
-    Tool arguments come from model output, so keep them O(n)."""
-    import time
-    from src.tool_implementations import do_manage_calendar
-
-    owner = "tester-" + uuid.uuid4().hex[:6]
-    started = time.perf_counter()
-    res = await do_manage_calendar(json.dumps({
-        "action": "create_event",
-        "summary": "Flood",
-        "dtstart": "2030-04-01T10:00:00",
-        "reminder_minutes": "0" * 40_000 + "x",
-        "duration": "0" * 40_000 + "x",
-    }), owner=owner)
-    assert time.perf_counter() - started < 2.0
-    assert res.get("exit_code") == 0, res
-    assert "reminder set" not in res.get("response", ""), res
-
-    # A reminder is set, so the "is the description only a reminder?" check runs.
-    started = time.perf_counter()
-    res = await do_manage_calendar(json.dumps({
-        "action": "create_event",
-        "summary": "Flood 2",
-        "dtstart": "2030-04-02T10:00:00",
-        "description": "alarm" + "\t" * 40_000,
-        "reminder_minutes": 5,
-    }), owner=owner)
-    assert time.perf_counter() - started < 2.0
-    assert res.get("exit_code") == 0, res
-    assert "reminder 5 min before" in res.get("response", ""), res