Walhalla

A utility class for managing and updating open2ch threads related to "Aigis".

This class performs the following operations:

• Fetches a list of recent threads using the open2ch search service.
• Determines whether each thread needs to be updated based on post count and last modified time.
• Launches the thread in a browser and collects the HTML source via a temporary local HTTP server.
• Saves the updated HTML source to local storage.

Returns a signal (reactive stream) of all parsed thread data. If this is the first call, it triggers the update process.