fix(multiplayer): persist arena identity on allocations

server/migrations/0009_allocation_arena_paths.sql

@@ -0,0 +1,4 @@
+-- Keep arena identity in the durable provider allocation record so retries
+-- and provider recovery compare the complete match compatibility tuple.
+ALTER TABLE allocations
+    ADD COLUMN arena_path TEXT;

server/migrations/down/0009_allocation_arena_paths.sql

@@ -0,0 +1,2 @@
+ALTER TABLE allocations
+    DROP COLUMN IF EXISTS arena_path;

server/migrations/test_migration.py

@@ -8,6 +8,7 @@ SQL = (Path(__file__).parent / "0001_initial.sql").read_text()
 ASSIGNMENTS_SQL = (Path(__file__).parent / "0002_assignments.sql").read_text()
 QUOTAS_SQL = (Path(__file__).parent / "0007_allocation_quotas.sql").read_text()
 ARENAS_SQL = (Path(__file__).parent / "0008_match_arena_paths.sql").read_text()
+ALLOCATION_ARENAS_SQL = (Path(__file__).parent / "0009_allocation_arena_paths.sql").read_text()
 
 
 class MigrationTest(unittest.TestCase):
@@ -68,6 +69,10 @@ class MigrationTest(unittest.TestCase):
         ):
             self.assertIn(fragment, ARENAS_SQL)
 
+    def test_provider_allocation_retains_arena_identity(self):
+        self.assertIn("ALTER TABLE allocations", ALLOCATION_ARENAS_SQL)
+        self.assertIn("ADD COLUMN arena_path TEXT", ALLOCATION_ARENAS_SQL)
+
 
 if __name__ == "__main__":
     unittest.main()