macos build and miri check to nightly

[harsha-simhadri]

Created nightly ci run; moved miri to nightly. added back macos build test.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.47%. Comparing base (f4757a3) to head (0b609f8).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1058      +/-   ##
==========================================
- Coverage   89.51%   89.47%   -0.04%     
==========================================
  Files         459      459              
  Lines       85646    85563      -83     
==========================================
- Hits        76663    76555     -108     
- Misses       8983     9008      +25     

Flag	Coverage Δ
miri	89.47% <ø> (-0.04%)	⬇️
unittests	89.09% <ø> (-0.04%)	⬇️

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see 42 files with indirect coverage changes

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[Copilot]

Pull request overview

Adds a dedicated scheduled “Nightly” GitHub Actions workflow to run macOS clippy/tests and moves the Miri job out of the main CI workflow into this nightly run.

Changes:

• Added .github/workflows/nightly.yml scheduled workflow (macOS clippy + workspace tests, plus Ubuntu Miri).
• Removed the standalone miri job from .github/workflows/ci.yml.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
.github/workflows/nightly.yml	New nightly workflow running macOS clippy/tests and a nightly-toolchain Miri job.
.github/workflows/ci.yml	Removes the previous Miri job from the main CI workflow.

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