fix: resolve duel roots and recover legacy snake data

- Resolve selected moves and enemy replies on the same simulated turn.
- Add an Apex candidate hook and bump the Prism snake to version 1.1.0.
- Rebuild benchmark states from normalized turn data when snapshots are empty.
- Synthesize missing game snake identities during legacy database migration.
- Add regression coverage for duel timing and partial legacy schemas.

tests/test_MigrateGameplayDatabase.py

@@ -47,6 +47,54 @@ class TestMigrateGameplayDatabase(unittest.TestCase):
         '{"color":"#663399","head":"ferret","tail":"swirl"}',
       ))
 
+  def test_copy_game_snakes_synthesizes_rows_when_table_is_empty(self):
+    source = sqlite3.connect(":memory:")
+    destination = sqlite3.connect(":memory:")
+    try:
+      source.execute("""
+        CREATE TABLE game_snakes (
+          game_id TEXT, snake_id TEXT, snake_name TEXT, is_you INTEGER,
+          customizations_json TEXT NOT NULL DEFAULT '{}'
+        )
+      """)
+      source.execute("""
+        CREATE TABLE snake_turns (
+          game_id TEXT, snake_id TEXT, snake_name TEXT, is_you INTEGER
+        )
+      """)
+      source.executemany(
+        "INSERT INTO snake_turns VALUES (?, ?, ?, ?)",
+        [
+          ("game-1", "snake-1", "PrismBattleSnake", 1),
+          ("game-1", "snake-1", "PrismBattleSnake", 1),
+          ("game-1", "snake-2", "Enemy", 0),
+        ],
+      )
+      destination.execute("""
+        CREATE TABLE game_snakes (
+          game_id TEXT, snake_id TEXT, snake_name TEXT, is_you INTEGER,
+          customizations_json TEXT NOT NULL DEFAULT '{}',
+          PRIMARY KEY (game_id, snake_id)
+        )
+      """)
+
+      copied = copy_game_snakes(
+        source, destination, batch_size=10, retained_ids={"game-1"},
+      )
+      rows = destination.execute("""
+        SELECT snake_id, snake_name, is_you, customizations_json
+        FROM game_snakes ORDER BY snake_id
+      """).fetchall()
+    finally:
+      source.close()
+      destination.close()
+
+    self.assertEqual(copied, 2)
+    self.assertEqual(rows, [
+      ("snake-1", "PrismBattleSnake", 1, "{}"),
+      ("snake-2", "Enemy", 0, "{}"),
+    ])
+
   def test_copy_game_snakes_defaults_legacy_schema_to_empty_customizations(self):
     source = sqlite3.connect(":memory:")
     destination = sqlite3.connect(":memory:")
@@ -60,6 +108,11 @@ class TestMigrateGameplayDatabase(unittest.TestCase):
         "INSERT INTO game_snakes VALUES (?, ?, ?, ?)",
         ("game-1", "snake-1", "LegacySnake", 0),
       )
+      source.execute("""
+        CREATE TABLE snake_turns (
+          game_id TEXT, snake_id TEXT, snake_name TEXT, is_you INTEGER
+        )
+      """)
       destination.execute("""
         CREATE TABLE game_snakes (
           game_id TEXT, snake_id TEXT, snake_name TEXT, is_you INTEGER,