ci: run macOS x64 and musl tests on PRs only with the ci: full label

[wan9chi]

Motivation

The macOS x64 job is the slowest CI job and sets the wall time for every pull request: it takes 220–245s, while the next slowest, musl, takes ~130s. Its compile step takes the same ~30s as on arm64. The extra time is Rosetta translating each x64 binary (node, bun, deno, Chromium, Codex, tsgo, and each test binary) the first time it runs on a fresh runner. musl is next: it builds with no Rust cache inside the Alpine container (76s of its ~130s).

Pull requests now skip both jobs unless they have the ci: full label. Adding the label reruns CI with both jobs included, and done waits for them, so a labeled PR can't merge until they pass. Pushes to main and manual dispatches still always run them.

macOS x64 moves out of the test matrix into its own job, because a matrix exclude can't remove an include entry. It reuses the test steps through a YAML anchor.

🤖 Generated with Claude Code

[github-actions]

fspy benchmark

linux

dynamic/launch             change  -0.64%  [ -9.95% ..  +7.96%]  overhead  +262.56%
dynamic/access             change  -0.14%  [ -1.42% ..  +1.12%]  overhead   +11.85%
dynamic/access-relative    change  +0.35%  [ -1.04% ..  +1.17%]  overhead   +58.15%
dynamic/access-contended   change  +0.29%  [ -0.72% ..  +2.74%]  overhead   +13.77%
static/launch              change  +0.10%  [ -5.85% ..  +6.10%]  overhead  +741.51%
static/access              change  -0.09%  [ -1.12% ..  +0.86%]  overhead  +821.69%
static/access-relative     change  +0.16%  [ -1.10% ..  +1.53%]  overhead +1416.42%
static/access-contended    change  +0.36%  [ -0.50% ..  +1.12%]  overhead +3199.27%

macos

dynamic/launch             change  -0.25%  [ -4.18% ..  +4.53%]  overhead  +229.62%
dynamic/access             change  -1.97%  [-17.26% .. +18.07%]  overhead    +9.09%
dynamic/access-relative    change  +3.28%  [ -4.55% .. +52.67%]  overhead  +246.45%
dynamic/access-contended   change  +0.94%  [ -4.56% .. +10.68%]  overhead    +3.12%

windows

dynamic/launch             change  -2.45%  [ -8.49% ..  +7.35%]  overhead   +23.41%
dynamic/access             change  -0.18%  [ -7.57% ..  +8.07%]  overhead    +1.46%
dynamic/access-relative    change  +0.17%  [-12.83% .. +16.88%]  overhead    +1.58%
dynamic/access-contended   change  -0.67%  [ -7.31% .. +11.27%]  overhead    +1.88%