ci: update workflows

[Nytelife26]

Closes #1392, #1395.

• update labels
• use actions/checkout@v5 (avoids ci-lint-test to prevent conflicts on ci: use nix for workflows #1416)
• use crazy-max/ghaction-github-labeler@v5
• remove cd-site
• label: update master -> main

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.34%. Comparing base (b481488) to head (353412b).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1419   +/-   ##
=======================================
  Coverage   94.34%   94.34%           
=======================================
  Files          99       99           
  Lines         796      796           
=======================================
  Hits          751      751           
  Misses         45       45           

Flag	Coverage Δ
macos-latest	94.34% <ø> (ø)
py3.10	94.22% <ø> (ø)
py3.11	94.22% <ø> (ø)
py3.12	94.22% <ø> (ø)
py3.13	93.59% <ø> (ø)
py3.9	94.08% <ø> (ø)
ubuntu-latest	94.34% <ø> (ø)
windows-latest	94.34% <ø> (ø)

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