feat(backup): v3 backup covers rulebooks, rules, events + join tables

The v2 backup silently dropped the entire rulebook system (rulebooks, topics,
rules), the project subscription/suppression join tables, and events — so a
'full' backup wasn't. v3 adds all of them with FK re-mapping on restore, and a
_not_included field that names the still-deferred tables (ACL groups/shares,
api_keys, embeddings, transient/operational) so the gap is explicit, not silent.

restore_full_backup routes v2 and v3 through one path; v3-only sections are
guarded by data.get so a v2 payload still restores cleanly.

Tests: version/coverage constants, pure join-table row helpers, and the export
contract via a mocked session (CI has no DB; full round-trip is a manual check).

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

tests/test_services_backup.py

@@ -0,0 +1,72 @@
+"""Unit tests for the v3 backup export contract.
+
+CI runs pytest with no database, so these cover the parts that don't need one:
+the version/coverage constants, the pure join-table row helpers, and the export
+dict shape (via a mocked session). Full FK-remapping round-trip is exercised
+manually against a real DB (export a backup, confirm rulebooks/events appear).
+"""
+from types import SimpleNamespace
+from unittest.mock import patch
+
+import pytest
+
+from scribe.services import backup
+
+
+def test_backup_version_is_v3():
+    assert backup.BACKUP_VERSION == 3
+
+
+def test_not_included_lists_the_known_gaps():
+    # The deferred tables must be surfaced explicitly, not silently dropped.
+    for table in ("groups", "project_shares", "note_shares", "api_keys", "embeddings"):
+        assert table in backup._NOT_INCLUDED
+
+
+def test_join_table_row_helpers_are_pure():
+    subs = [SimpleNamespace(project_id=1, rulebook_id=2)]
+    rsup = [SimpleNamespace(project_id=1, rule_id=9)]
+    tsup = [SimpleNamespace(project_id=1, topic_id=7)]
+    assert backup._subscription_rows(subs) == [{"project_id": 1, "rulebook_id": 2}]
+    assert backup._rule_suppression_rows(rsup) == [{"project_id": 1, "rule_id": 9}]
+    assert backup._topic_suppression_rows(tsup) == [{"project_id": 1, "topic_id": 7}]
+
+
+class _Result:
+    def scalars(self):
+        return self
+
+    def all(self):
+        return []
+
+
+class _Session:
+    async def execute(self, *a, **k):
+        return _Result()
+
+    async def get(self, *a, **k):
+        return None
+
+
+class _CM:
+    async def __aenter__(self):
+        return _Session()
+
+    async def __aexit__(self, *a):
+        return False
+
+
+@pytest.mark.asyncio
+async def test_export_full_backup_contains_v3_sections():
+    with patch("scribe.services.backup.async_session", lambda: _CM()):
+        out = await backup.export_full_backup()
+
+    assert out["version"] == 3
+    assert out["scope"] == "full"
+    assert "api_keys" in out["_not_included"]
+    # The sections v2 silently dropped must now be present (empty here).
+    for key in ("rulebooks", "rulebook_topics", "rules",
+                "rulebook_subscriptions", "rule_suppressions",
+                "topic_suppressions", "events"):
+        assert key in out, f"missing v3 section: {key}"
+        assert out[key] == []