fix(datasources): preserve governed CSV originals and fresh detail state

Release v0.1.26. Coordinated integrity review: GovOPlaN/govoplan-core#298.

tests/test_lifecycle_governance.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from govoplan_core.core.tabular_sources import TabularCsvSource
+
 import unittest
 from datetime import timedelta
 
@@ -345,6 +347,7 @@ class DatasourceLifecycleGovernanceTests(unittest.TestCase):
                 mode="static",
                 shape="tabular",
                 rows=({"id": 1},),
+                csv_source=TabularCsvSource(text="id\n1\n"),
                 governance=governance,
             ),
         )
@@ -389,6 +392,7 @@ class DatasourceLifecycleGovernanceTests(unittest.TestCase):
             )
         )
         payload_id = first_row.payload_id
+        self.assertIsNotNone(first_row.csv_source_)
         disposed, evidence_hashes = self.provider.apply_retention(
             self.session,
             principal("admin", scopes=("datasources:source:admin",)),
@@ -400,6 +404,7 @@ class DatasourceLifecycleGovernanceTests(unittest.TestCase):
         self.assertEqual(1, len(evidence_hashes))
         self.assertIsNone(self.session.get(DatasourcePayloadRecord, payload_id))
         self.assertIsNotNone(first_row.disposed_at)
+        self.assertIsNone(first_row.csv_source_)
         self.assertEqual("disposed", first_row.state)
         with self.assertRaises(DatasourceUnavailableError):
             self.provider.read_datasource(
@@ -446,6 +451,7 @@ class DatasourceLifecycleGovernanceTests(unittest.TestCase):
                 mode="static",
                 shape="tabular",
                 rows=({"id": 1},),
+                csv_source=TabularCsvSource(text="id\n1\n"),
                 governance=DatasourceGovernance(
                     retention_policy={
                         "version": "stage-retention-v1",