DM-47673: v28 release notes (cherry-picked)

[timj]

Checklist

• ran Jenkins
• added a release note for user-visible changes to doc/changes
• (if changing dimensions.yaml) make a copy of dimensions.yaml in configs/old_dimensions

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.44%. Comparing base (53005fb) to head (bbe503a).
Report is 6 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1120   +/-   ##
=======================================
  Coverage   89.44%   89.44%           
=======================================
  Files         366      366           
  Lines       48604    48604           
  Branches     5890     5890           
=======================================
  Hits        43475    43475           
  Misses       3717     3717           
  Partials     1412     1412           

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