* allow beat tasks to expire. it isn't important that they all run
* validate fences are in a good state and cancel/fail them if not
* add function timings for important beat tasks
* optimize lookups, add lots of comments
* review changes
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Co-authored-by: Richard Kuo <rkuo@rkuo.com>
Co-authored-by: Richard Kuo (Danswer) <rkuo@onyx.app>