chore: Separate nightly

[dipinknair]

Nightly workflow (summary)

What: .github/workflows/nightly.yml runs on a daily schedule (22:00 UTC) and manual dispatch. It runs Mechanical embedding, remote connect, embedding scripts, and launch tests, merges coverage, deletes untagged GHCR package versions for ansys/mechanical, and notifies Teams on failure.

What it skips: Code style, documentation style, smoke/wheelhouse matrix, security audits, and documentation build (those stay on the main .github/workflows/ci_cd.yml workflow).

Related: Ad hoc untagged-package cleanup only → .github/workflows/package_cleanup.yml.

---

Closes #603

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.28%. Comparing base (6607e79) to head (856de9e).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1562   +/-   ##
=======================================
  Coverage   80.28%   80.28%           
=======================================
  Files          42       42           
  Lines        3191     3191           
=======================================
  Hits         2562     2562           
  Misses        629      629           

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[github-actions]

The documentation for this pull request will be available at https://mechanical.docs.pyansys.com/pull/1562. Please allow some time for the documentation to be deployed.

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

🟢 Coverage ∅ diff coverage · +0.00% coverage variation

Metric	Results
Coverage variation	✅ +0.00% coverage variation (-1.00%)
Diff coverage	✅ ∅ diff coverage

View coverage diff in Codacy

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (6607e79)	3191	2562	80.29%
Head commit (856de9e)	3191 (+0)	2562 (+0)	80.29% (+0.00%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#1562)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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