[codeforester]

Closes #78.

Part of the coordinated train anchored by basefoundry/base#2604.

Changes:

• Moves Homebrew Bash, standalone artifact, and framework-compatibility jobs to pinned macos-15.
• Updates the required-check aggregate and CI documentation.
• Preserves historical macos-14 evidence.

Local validation:

• Full tests/validate.sh passed after preparing the pinned SPDX validator with the normal setup contract.
• git diff --check passed.

[codeforester]

Review: the change itself is correct, but this PR cannot go green as-is. Required consumer and artifact validation is structurally unable to pass. Reviewed all 4 files at 5f344c1.

Blocking: the required-check poller runs from main, not from this branch

required-checks.yml triggers on pull_request_target, so GitHub loads the workflow definition from main, where expected_names_json still lists Standalone artifact (macos-14). This PR's tests.yml now emits Standalone artifact (macos-15), so the poller sees Standalone artifact (macos-14)=missing/pending on every attempt and exits with "Timed out waiting for the pull-request test lanes for 5f344c1…" (run 38950549061). The required-checks.yml edit in this PR therefore cannot affect its own check. That check is a required status in the "Base default branch protection" ruleset, and the ruleset has no bypass actors.

Every lane it is waiting on is in fact green: Ubuntu validation, Minimum runtime (Bash 4.2.53), macOS Homebrew Bash validation, and Standalone artifact (ubuntu-24.04) and (macos-15).

Ways forward:

1. The workflow has a workflow_dispatch entry (inputs pull_request_number, head_sha). Dispatching it from the PR branch should run this branch's copy of the file:
   gh workflow run required-checks.yml --ref ci/78-20261017-move-demo-validation-from-macos-14-to-macos-15 -f pull_request_number=79 -f head_sha=5f344c175e8856227bca882d5fe098833363faef
   If the ruleset accepts that run's check for the same name, this is the lightest fix. Please confirm it actually satisfies the required status before relying on it.
2. If it does not, use a two-step change: first a main-side change so the poller tolerates either name for the macOS leg (or derives the expected lanes from tests.yml), then this rename, then drop the tolerance. The alternative is relaxing the ruleset for this one merge.

Unrelated failure: Sync issue and PR Project fields (Project Intake) failed on a GitHub GraphQL rate limit ("API rate limit already exceeded") while linking the PR to the issue, after its one retry. Re-run the failed job; it is not caused by this diff.

Otherwise fine: no macos-14 remains anywhere on the branch (workflows or docs), and the three workflow edits and the doc line match the issue scope. Supported Bash/Homebrew and Ubuntu behaviour is untouched. The acceptance criterion "required-check polling expects the new macos-15 check name" is met by the diff; it just cannot be demonstrated by this PR's own run.

[codeforester]

This edit cannot take effect for this PR's own run: pull_request_target loads required-checks.yml from main, which still expects Standalone artifact (macos-14). See the review summary for ways forward.