[Improved, Fixed] Automations activity performance

Improvements

• The Automations activity tab now loads run history and each run’s job list incrementally (20 at a time) for noticeably faster scrolling and page load times.
• Expanded run details appear in a capped, scrollable panel with a pinned header, so long histories stay readable without pushing the rest of the page off-screen.

Fixes

• Fixed a problem that caused the activity tab to freeze and render hundreds of off-screen rows when viewing runs with large job counts.