ensure nightly builds always produce new packages, expand 'changed-files' lists

[jameslamb]

Contributes to rapidsai/build-planning#218

• uses the new patterns for versioning nightly packages (see builds: add support for computing a date-based version component at build time rapidsai/shared-workflows#603), to ensure they're always uploaded on new builds.

For wheels:

# before
26.10.0a55 

# after
26.10.0a55.post260803200854

And for conda:

# before
26.10.0a55[build=cuda12_260803_9da146ef]

# after
26.10.0a55[build=cuda12_260803200854_9da146ef]

Other changes:

• updates changed-files lists to avoid triggering test jobs in PR CI when only .github/workflows/{build,test}.yaml are changed

Notes for Reviewers

How I tested this

See rapidsai/cugraph-gnn#508

[coderabbitai]

📝 Walkthrough

Summary by CodeRabbit

• Build and Packaging

  • Build artifacts and package versions now include a consistent, more precise datetime identifier.
  • Wheel and Conda package build strings use the updated timestamp format.
  • C++ and Python builds now receive the same build datetime information.

• CI Improvements

  • Pull request and build workflows share build metadata consistently.
  • Workflow change detection avoids unnecessary rebuilds for unrelated configuration updates.

Walkthrough

The workflows now generate one shared build datetime and pass it to C++, Python, Conda, and wheel builds. Build scripts and recipes use RAPIDS_DATETIME_STRING. Wheel versions receive a .post suffix.

Changes

Build datetime workflow integration

Layer / File(s)	Summary
Workflow build datetime propagation .github/workflows/build.yaml, .github/workflows/pr.yaml	Adds the reusable build-details job and passes its build-datetime output to C++, Python, Conda, and wheel jobs.
Workflow changed-file filters .github/workflows/pr.yaml	Excludes build.yaml and test.yaml from the relevant changed-file filters.
Build timestamp consumers ci/build_*.sh, conda/recipes/*/recipe.yaml	Replaces RAPIDS_DATE_STRING with RAPIDS_DATETIME_STRING. Conda build strings and wheel version files use the datetime value.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Possibly related PRs

• rapidsai/cudf#23174: Both PRs modify wheel-build jobs in the CI workflows, but this PR changes build metadata and dependencies.

Suggested reviewers: msarahan

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	The title clearly summarizes the nightly package versioning and changed-files workflow updates.
Description check	✅ Passed	The description directly explains the nightly package versioning changes and changed-files workflow updates.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

_{Comment @coderabbitai help to get the list of available commands.}

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@conda/recipes/libcudf/recipe.yaml`:
- Line 305: Move the string key from the build.script.env section to the build
level, alongside the script configuration, while preserving its existing
cuda_major, datetime_string, and head_rev expression so libcudf-example receives
the intended unique build string.

🪄 Autofix

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: a839e81f-3a26-4bd3-a547-d2c41e025c81

📥 Commits

Reviewing files that changed from the base of the PR and between 079ebcb and bb48ae0.

📒 Files selected for processing (14)

• .github/workflows/build.yaml
• .github/workflows/pr.yaml
• ci/build_cpp.sh
• ci/build_python.sh
• ci/build_python_noarch.sh
• ci/build_wheel.sh
• conda/recipes/cudf-polars/recipe.yaml
• conda/recipes/cudf/recipe.yaml
• conda/recipes/cudf_kafka/recipe.yaml
• conda/recipes/cudf_streaming/recipe.yaml
• conda/recipes/custreamz/recipe.yaml
• conda/recipes/dask-cudf/recipe.yaml
• conda/recipes/libcudf/recipe.yaml
• conda/recipes/pylibcudf/recipe.yaml

[jameslamb]

/merge