Add functionality to enable/disable

[fukawi2]

Adds two new user preferences for toggling existing K2 features on or off. Both default to on so existing users see no behaviour change.

• Auto-clicking GitHub's "Load more" buttons on issue/PR pages.
• The "Open All" buttons on dashboard panel headers.

The auto-load-more toggle lives in the issue/PR sidebar under the existing "Show/Hide Timestamps" toggle, and the Open All toggle lives on the K2 dashboard inside Legend.

Implementation notes:

• New preference helpers get/setAutoLoadMoreComments and get/setShowOpenAllButtons in Preferences.js, both treating an unset value as true.
• autoLoadMoreComments.js was refactored into start / stop / initAutoLoadMoreComments. The init subscribes to Onyx PREFERENCES, so flipping the toggle starts/stops the MutationObserver live without a page reload.
• The shared Title component (used by every dashboard panel) now subscribes to Onyx itself and gates the Open All button on showOpenAllButtons, so no consumer needed to change.
  • pr.js refreshSidebar was slightly restructured to support multiple toggle wrappers — the previous early-return-after-timestamp-wrapper flow couldn't accommodate a second sibling wrapper.

[iwiznia]

If you have tested that both features work when enabled and do not work when disabled, feel free to merge.

[fukawi2]

I have tested it works both ways, and switching between them works as expected.

[os-botify]

🚀 Released in version 1.5.42 🚀