fix(trash): owner-scope all trash ops — close cross-tenant IDOR/disclosure

Drift-audit Group 1 (authz/IDOR). Multi-user is live, so these were
exploitable ACL bypasses:

- trash.py: add _owner_clause() and apply it to _exists_alive, restore,
  purge, list_trash, and purge_expired. A batch_id is a bearer token;
  without an owner predicate a leaked/guessed id let one tenant read
  (list_trash), restore, or PERMANENTLY purge another's content. Topics
  and rules carried no owner check at all (_OWNER mapped them to None) —
  ownership now derives through the parent rulebook (or owning project,
  for project-scoped rules).
- purge_expired is now per-user; trash_scheduler iterates every user and
  applies that user's own trash_retention_days window, instead of
  applying user 1's window to everyone (early data loss for other users).
- rulebooks subscribe/unsubscribe_project now assert project ownership,
  matching the suppression endpoints.
- topic/rule DELETE routes return 404 when nothing owned was removed.

Regression test locks in that every model — including topics/rules —
gets a real owner clause.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_services_trash.py

@@ -112,7 +112,7 @@ async def test_purge_expired_skips_when_retention_zero():
     with patch("fabledassistant.services.trash.async_session") as cls:
         cls.return_value = session
         from fabledassistant.services.trash import purge_expired
-        n = await purge_expired(0)
+        n = await purge_expired(1, 0)
     assert n == 0
     assert not session.execute.called  # never opens a delete
 
@@ -124,11 +124,34 @@ async def test_purge_expired_deletes_across_models_when_positive():
     with patch("fabledassistant.services.trash.async_session") as cls:
         cls.return_value = session
         from fabledassistant.services.trash import purge_expired
-        n = await purge_expired(90)
+        n = await purge_expired(1, 90)
     assert n == 7
     assert session.execute.await_count == 7
 
 
+def test_owner_clause_scopes_every_model():
+    """Regression: every trash op must owner-scope, including topics/rules
+    which previously had NO owner check (IDOR across tenants)."""
+    from fabledassistant.services.trash import _owner_clause, _MODEL_FOR
+    from fabledassistant.models.note import Note
+    from fabledassistant.models.rulebook import Rulebook, RulebookTopic, Rule
+
+    # Models with a direct owner column.
+    assert "user_id" in str(_owner_clause(Note, 7))
+    assert "owner_user_id" in str(_owner_clause(Rulebook, 7))
+
+    # Topics/rules carry no user_id — ownership is derived through the
+    # parent rulebook (and, for rules, the owning project).
+    topic_sql = str(_owner_clause(RulebookTopic, 7))
+    assert "rulebooks" in topic_sql and "owner_user_id" in topic_sql
+    rule_sql = str(_owner_clause(Rule, 7))
+    assert "owner_user_id" in rule_sql and "projects" in rule_sql
+
+    # Every entity type resolves to a model that yields a non-empty clause.
+    for model in set(_MODEL_FOR.values()):
+        assert _owner_clause(model, 1) is not None
+
+
 @pytest.mark.asyncio
 async def test_list_trash_groups_by_batch():
     session = _make_mock_session()