Update README with detailed guide

[Borda]

This pull request primarily improves the project documentation and the developer experience by making the README much more comprehensive and user-friendly, and by updating GitHub Actions workflow files for clarity and maintainability. The most significant changes are grouped below by theme.

Documentation improvements:

• Major rewrite and expansion of README.md to include detailed setup instructions, workflow explanations, free tier usage, trigger rationale, and visual aids. The new README makes it much easier for new users to understand, adopt, and adapt the GPU CI setup using Modal.

Workflow and CI enhancements:

• Updated step names in .github/workflows/_modal-gpu-tests.yml, .github/workflows/ci_testing.yml, and .github/workflows/label-gpu-tests.yml to include emojis and more descriptive labels, improving readability and making CI logs easier to scan. [1] [2] [3] [4] [5]
• Changed the branch trigger in .github/workflows/run-gpu-tests.yml to only run on main instead of both main and develop, simplifying the workflow triggers.

[github-actions]

🎮 GPU Test Results

✅ Tests Passed

Summary: ============================== 10 passed in 0.24s ==============================

Full Test Output

============================= test session starts ==============================
platform linux -- Python 3.10.13, pytest-9.0.2, pluggy-1.6.0 -- /usr/local/bin/python
cachedir: .pytest_cache
rootdir: /root/project
configfile: pyproject.toml
plugins: anyio-4.12.1
collecting ... collected 10 items

tests/test_math_ops.py::test_power[2-3-8.0] PASSED                       [ 10%]
tests/test_math_ops.py::test_power[5-0-1.0] PASSED                       [ 20%]
tests/test_math_ops.py::test_power[10-1-10.0] PASSED                     [ 30%]
tests/test_math_ops.py::test_power[2--1-0.5] PASSED                      [ 40%]
tests/test_math_ops.py::test_power[0-5-0.0] PASSED                       [ 50%]
tests/test_math_ops.py::test_power[3-3-27.0] PASSED                      [ 60%]
tests/test_math_ops.py::test_power_identity PASSED                       [ 70%]
tests/test_math_ops.py::test_power_zero_exponent PASSED                  [ 80%]
tests/test_math_ops.py::test_power_negative_exponent PASSED              [ 90%]
tests/test_math_ops.py::test_power_fractional_exponent PASSED            [100%]

============================== 10 passed in 0.24s ==============================

Workflow Run: https://github.com/Borda/affordable-GPU-CI_Modal/actions/runs/22310397715

[Copilot]

Pull request overview

This PR expands the project documentation to better explain the “GPU CI on Modal” approach and polishes GitHub Actions workflow readability, while also narrowing the GPU test workflow’s branch trigger to main.

Changes:

• Major rewrite/expansion of README.md with setup, workflow explanations, and visuals.
• Renamed GitHub Actions step names (emojis + clearer labels) for easier CI log scanning.
• Updated run-gpu-tests.yml push trigger to run only on main.

Reviewed changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
README.md	Adds comprehensive “how it works”/setup guide, examples, and a screenshot reference.
.github/workflows/_modal-gpu-tests.yml	Step name updates for readability in the reusable GPU workflow.
.github/workflows/ci_testing.yml	Step name updates for readability in CPU CI workflow.
.github/workflows/label-gpu-tests.yml	Step name updates for readability in the PR-label triggered workflow.
.github/workflows/run-gpu-tests.yml	Restricts push trigger to main (and keeps manual dispatch).
.assets/gh-comment-modal.webp	Adds an image used by the README to illustrate PR comment output.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 6 changed files in this pull request and generated no new comments.

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