Auto-open entries when opening a category

[temyy]

Could be useful to have a setting to auto-open an entry in a category when said category is opened, either only for the first time or every time said category is opened. Likely preferable to have the setting in category.json (something like "auto_open": "category:entry", "open_on": "first/always") instead of entry.json, unless youd want multiple entries opening automatically (why tho?)