chore: Finalize changes to build size action

[metal-messiah]

Track build sizes using shared GHA

Track build sizes for:

• Pull request builds
• merges with main branch
• nightly checks
• new releases

[github-actions]

Asset Size Report

Merging this pull request will result in the following asset size changes:

Agent	Asset	Previous Size	New Size	Diff
lite	loader	29.77 kB / 10.79 kB (gzip)	29.77 kB / 10.79 kB (gzip)	0% / 0% (gzip)
lite	async-chunk	52.59 kB / 17.08 kB (gzip)	52.59 kB / 17.08 kB (gzip)	0% / 0% (gzip)
pro	loader	51.42 kB / 17.74 kB (gzip)	51.42 kB / 17.74 kB (gzip)	0% / 0% (gzip)
pro	async-chunk	99.77 kB / 30.52 kB (gzip)	99.77 kB / 30.52 kB (gzip)	0% / 0% (gzip)
spa	loader	59.04 kB / 20.07 kB (gzip)	59.04 kB / 20.07 kB (gzip)	0% / 0% (gzip)
spa	async-chunk	114.49 kB / 34.85 kB (gzip)	114.49 kB / 34.85 kB (gzip)	0% / 0% (gzip)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.65%. Comparing base (429a7b6) to head (f907290).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1300      +/-   ##
==========================================
- Coverage   88.68%   88.65%   -0.04%     
==========================================
  Files         170      170              
  Lines        7317     7324       +7     
  Branches     1480     1497      +17     
==========================================
+ Hits         6489     6493       +4     
- Misses        714      716       +2     
- Partials      114      115       +1     

Flag	Coverage Δ
unit-tests	79.93% <ø> (+0.03%)	⬆️

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