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.

scripts/benchmark_snakes_from_db.py

@@ -31,7 +31,8 @@ def load_states(db_path: str, samples: int, stride: int) -> list[tuple[dict, dic
   states: list[tuple[dict, dict]] = []
   next_id = max(1, max_id - (samples - 1) * stride)
   query = """
-    SELECT t.board_state_json, t.you_json, g.your_snake_id,
+    SELECT t.id, t.board_state_json, t.you_json, t.food_json, t.hazards_json,
+           g.your_snake_id, g.your_snake_name, g.width, g.height,
            g.game_id, g.source, g.map_name,
            g.ruleset_name, g.ruleset_version, t.turn
     FROM turns AS t
@@ -40,30 +41,65 @@ def load_states(db_path: str, samples: int, stride: int) -> list[tuple[dict, dic
     ORDER BY t.id
     LIMIT 1
   """
+  snake_query = """
+    SELECT st.snake_id, COALESCE(gs.snake_name, st.snake_name),
+           st.health, st.length, st.head_x, st.head_y, st.body_json,
+           COALESCE(gs.customizations_json, '{}')
+    FROM snake_turns AS st
+    LEFT JOIN game_snakes AS gs
+      ON gs.game_id = st.game_id AND gs.snake_id = st.snake_id
+    WHERE st.game_id = ? AND st.turn = ?
+    ORDER BY st.id
+  """
   while len(states) < samples and next_id <= max_id:
     row = connection.execute(query, (next_id,)).fetchone()
     if row is None:
       break
-    board = json.loads(row[0])
-    you = json.loads(row[1])
+    board = json.loads(row[1])
+    you = json.loads(row[2])
+    if not board.get("snakes"):
+      snakes = []
+      for snake_row in connection.execute(snake_query, (row[9], row[14])):
+        snake_id = snake_row[0]
+        snake_name = snake_row[1] or (row[6] if snake_id == row[5] else snake_id)
+        body = json.loads(snake_row[6])
+        snakes.append({
+          "id": snake_id,
+          "name": snake_name,
+          "health": snake_row[2],
+          "length": snake_row[3],
+          "head": {"x": snake_row[4], "y": snake_row[5]},
+          "body": body,
+          "customizations": json.loads(snake_row[7]),
+        })
+      board = {
+        "width": row[7],
+        "height": row[8],
+        "food": json.loads(row[3]),
+        "hazards": json.loads(row[4]),
+        "snakes": snakes,
+      }
     if not you:
       you = next(
-        (snake for snake in board.get("snakes", []) if snake.get("id") == row[2]),
+        (snake for snake in board.get("snakes", []) if snake.get("id") == row[5]),
         {},
       )
+    if not you or not board.get("snakes"):
+      next_id = int(row[0]) + stride
+      continue
     metadata = {
-      "game_id": row[3],
-      "source": row[4] or "custom",
-      "map": row[5] or "standard",
+      "game_id": row[9],
+      "source": row[10] or "custom",
+      "map": row[11] or "standard",
       "ruleset": {
-        "name": row[6] or "standard",
-        "version": row[7] or "v1.0.0",
+        "name": row[12] or "standard",
+        "version": row[13] or "v1.0.0",
         "settings": {},
       },
-      "turn": int(row[8]),
+      "turn": int(row[14]),
     }
     states.append((board, {"you": you, **metadata}))
-    next_id += stride
+    next_id = int(row[0]) + stride
   connection.close()
   return states
 

scripts/migrate_gameplay_database.py

@@ -143,6 +143,12 @@ def copy_game_snakes(source:sqlite3.Connection, destination:sqlite3.Connection,
   has_game_snakes = source.execute("""
     SELECT 1 FROM sqlite_master WHERE type = 'table' AND name = 'game_snakes'
   """).fetchone() is not None
+  sql = """
+    INSERT OR IGNORE INTO game_snakes (
+      game_id, snake_id, snake_name, is_you, customizations_json
+    ) VALUES (?, ?, ?, ?, ?)
+  """
+  count = 0
   if has_game_snakes:
     columns = object_columns(source, "game_snakes")
     customizations = (
@@ -153,24 +159,26 @@ def copy_game_snakes(source:sqlite3.Connection, destination:sqlite3.Connection,
       SELECT game_id, snake_id, snake_name, is_you, {customizations}
       FROM game_snakes ORDER BY game_id, snake_id
     """)
-  else:
-    cursor = source.execute("""
-      SELECT game_id, snake_id, MAX(snake_name), MAX(is_you),
-        '{}' AS customizations_json
-      FROM snake_turns
-      GROUP BY game_id, snake_id
-      ORDER BY game_id, snake_id
-    """)
-  sql = """
-    INSERT INTO game_snakes (
-      game_id, snake_id, snake_name, is_you, customizations_json
-    ) VALUES (?, ?, ?, ?, ?)
-  """
-  count = 0
+    while rows := cursor.fetchmany(batch_size):
+      retained_rows = [tuple(row) for row in rows if row[0] in retained_ids]
+      before = destination.total_changes
+      destination.executemany(sql, retained_rows)
+      count += destination.total_changes - before
+
+  # Older databases can contain an empty or only partially populated
+  # game_snakes table. Always synthesize missing identities from snake_turns.
+  cursor = source.execute("""
+    SELECT game_id, snake_id, MAX(snake_name), MAX(is_you),
+      '{}' AS customizations_json
+    FROM snake_turns
+    GROUP BY game_id, snake_id
+    ORDER BY game_id, snake_id
+  """)
   while rows := cursor.fetchmany(batch_size):
     retained_rows = [tuple(row) for row in rows if row[0] in retained_ids]
+    before = destination.total_changes
     destination.executemany(sql, retained_rows)
-    count += len(retained_rows)
+    count += destination.total_changes - before
   return count
 
 def decode_json(value:str|None, fallback):