chore: consolidate platform split checks

tests/test_pagination.py

@@ -0,0 +1,33 @@
+from __future__ import annotations
+
+import unittest
+
+from govoplan_core.core.pagination import (
+    KeysetCursorError,
+    decode_keyset_cursor,
+    encode_keyset_cursor,
+    keyset_query_fingerprint,
+)
+
+
+class PaginationCursorTests(unittest.TestCase):
+    def test_keyset_cursor_round_trips_and_rejects_query_mismatch(self) -> None:
+        fingerprint = keyset_query_fingerprint("audit.admin", {"scope": "system", "page_size": 25})
+        cursor = encode_keyset_cursor(
+            "audit.admin",
+            fingerprint=fingerprint,
+            values={"id": "row-1", "sort_value": "2026-01-01T00:00:00+00:00"},
+        )
+
+        self.assertEqual(
+            decode_keyset_cursor("audit.admin", cursor, fingerprint=fingerprint),
+            {"id": "row-1", "sort_value": "2026-01-01T00:00:00+00:00"},
+        )
+        with self.assertRaises(KeysetCursorError):
+            decode_keyset_cursor("audit.admin", cursor, fingerprint=keyset_query_fingerprint("audit.admin", {"scope": "tenant"}))
+        with self.assertRaises(KeysetCursorError):
+            decode_keyset_cursor("files.list", cursor, fingerprint=fingerprint)
+
+
+if __name__ == "__main__":
+    unittest.main()