Global timing trend plot

It might be useful to have a trend plot like the one shown here https://testhub.mesastar.org/main/test_cases/star/c13_pocket?tab=trend that shows the timing difference between each commit across the test suite, or to make this data easily available to scrape so one can make a quick plot on global timing changes across different commits.

It might not be trivial to do this without checking for differences in hardward/#cpus/testing_flags, but if there was a figure, it could have the test_suite case number on the x-axis and time on the y-axis. Then one could plot say 5 lines consisting of 106 points each (or however many test cases there are), one line for each commit. So maybe this figure would show the timing changes across that last 5 commits made to main or something. There might be better ways of extracting or viewing this information.

This is a just a half formed idea at the moment. If something better is implemented or this is addressed in a different manner, feel free to close this issue.

Start by reviewing the existing test-suite timing and commit data represented by the linked trend view, then determine how hardware, CPU count, and testing flags are recorded. Define whether the first deliverable is a scrapeable data endpoint or a plot showing recent commits, test cases, and timing; the issue does not yet identify files, tests, or a settled completion criterion.

Written by the indexing model from the issue text.