This pull request introduces a new system for managing extra stage data in the game, along with enhancements to the replay system to support storing and retrieving this data. The changes include the addition of a new module ext_stage_data.lua, modifications to existing replay and stage management functions, and integration of the new system into the game's workflow.

New system for managing extra stage data:

• game/packages/thlib-scripts/THlib/ext/ext_stage_data.lua: Added a new module ext.stage_data to handle extra stage data, including methods for setting, retrieving, initializing, serializing, and preparing stage data. This module ensures type validation for keys and values and prevents data modification during replay mode.

Replay system enhancements:

• game/packages/thlib-scripts/THlib/ext/ext_replay.lua: Updated SaveReplay to store serialized stage data in the gameExtendInfo field and added logic in stage.Set to prepare stage data from replay files when available. [1] [2] [3] [4]

Integration of extra stage data into the game workflow:

• game/packages/thlib-scripts/THlib/ext/ext.lua: Integrated the new ext.stage_data module into the game by loading it in the initialization script and calling InitStageData during stage transitions. [1] [2]

Additional changes:

• game/packages/thlib-scripts/THlib/enemy/boss_system.lua: Added logic to record and retrieve boss timer data using the new ext.stage_data system, ensuring compatibility with replay mode.