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_session_endpoint_owner_scope.py

@@ -6,21 +6,13 @@ from fastapi import HTTPException
 
 # Import the route helper during collection so sibling session tests that use
 # partial import stubs do not become the first loader of core.session_manager.
-from routes.session_routes import (
-    _reject_delegated_session_options,
-    _reject_raw_endpoint_url_for_non_admin,
-)
+from routes.session_routes import _reject_raw_endpoint_url_for_non_admin
 
 
-def _request(user, *, admin=False, api_token=False, scopes=None):
+def _request(user, *, admin=False):
     auth_manager = SimpleNamespace(is_admin=lambda username: bool(admin))
     return SimpleNamespace(
-        state=SimpleNamespace(
-            current_user="api" if api_token else user,
-            api_token=api_token,
-            api_token_owner=user if api_token else None,
-            api_token_scopes=scopes or [],
-        ),
+        state=SimpleNamespace(current_user=user),
         app=SimpleNamespace(state=SimpleNamespace(auth_manager=auth_manager)),
     )
 
@@ -52,47 +44,6 @@ def test_admin_and_registered_endpoint_can_use_endpoint_url():
     )
 
 
-def test_bearer_token_does_not_inherit_owner_admin_raw_endpoint_authority():
-    request = _request("admin", admin=True, api_token=True, scopes=["chat"])
-
-    with pytest.raises(HTTPException) as exc:
-        _reject_raw_endpoint_url_for_non_admin(
-            request,
-            "admin",
-            "",
-            "http://127.0.0.1:8000/v1/chat/completions",
-        )
-
-    assert exc.value.status_code == 403
-
-
-def test_chat_scoped_bearer_can_still_choose_an_owner_registered_endpoint():
-    _reject_raw_endpoint_url_for_non_admin(
-        _request("admin", admin=True, api_token=True, scopes=["chat"]),
-        "admin",
-        "owner-endpoint-id",
-        "http://127.0.0.1:8000/v1/chat/completions",
-    )
-
-
-@pytest.mark.parametrize(
-    ("skip_validation", "api_key"),
-    [(True, ""), (False, "caller-secret")],
-)
-def test_bearer_token_cannot_use_interactive_session_options(
-    skip_validation,
-    api_key,
-):
-    with pytest.raises(HTTPException) as exc:
-        _reject_delegated_session_options(
-            _request("admin", admin=True, api_token=True, scopes=["chat"]),
-            skip_validation=skip_validation,
-            api_key=api_key,
-        )
-
-    assert exc.value.status_code == 403
-
-
 def test_chat_endpoint_recovery_paths_are_owner_scoped():
     root = Path(__file__).resolve().parents[1]
     chat_routes = (root / "routes" / "chat_routes.py").read_text(encoding="utf-8")