Docs: Local CI matrix (host, Docker, GHA skips) in README

[PurHur]

Problem

Contributors face three CI surfaces with different behavior:

Surface	LLVM	Serve tests	JIT compliance
Host ./script/ci-local.sh	.llvm/ if installed	runs unless PHP_COMPILER_SKIP_SERVE_TESTS	runs if LLVM present
Docker make test-docker	/opt/llvm9 in image (#237 closed)	same as host	should run (#98)
GitHub Actions .github/workflows/ci.yml	llvm job	skipped (PHP_COMPILER_SKIP_SERVE_TESTS=1)	llvm group

Without a single table, #98, #234, and #174 look like duplicate “fix CI” issues.

Goal

README (or docs/ci-local.md) documents what runs where and the local commands that must pass before merge — without requiring cloud CI.

Scope

• Table: host vs php-compiler:22.04-dev vs GHA (optional third column labeled “may skip”)
• Document env vars: PHP_COMPILER_SKIP_SERVE_TESTS, PHP_COMPILER_LLVM_PATH, PHP_COMPILER_RUN_SERVE_TESTS
• Canonical harness commands: make test-docker, ./script/docker-ci-local.sh
• Link Testing: Run HTTP serve integration tests in Docker local CI #234 (serve tests in Docker), CI: Run JIT compliance tests in CI (fix LLVM skip in PHPUnit) #98 (JIT must not be 100% skipped when LLVM present), Infrastructure: Publish Docker dev image and document container CI workflow #202 (publish image)
• Close or narrow Docs: Rewrite README feature list to match current compiler (2026) #48 README rewrite when capability section points here

Acceptance criteria

Fresh contributor can answer: “Will serve tests run on my laptop?” and “How do I reproduce GHA llvm job locally?” using only README/docs — no workflow edits required.

Verification

Review only — no GitHub Actions dependency.

Related

• DevEx: Document and stabilize host-based workflow (ci-local.sh, LLVM 9) #46, CI: Add GitHub Actions workflow for PHPUnit (VM, compliance, real, AOT) #47 (closed host/GHA baselines)
• CI: Run JIT compliance tests in CI (fix LLVM skip in PHPUnit) #98, Testing: Run HTTP serve integration tests in Docker local CI #234, Infrastructure: Publish Docker dev image and document container CI workflow #202, Infrastructure: Pre-install LLVM 9 in 22.04 dev Docker image for JIT/AOT CI #237
• Docs: Rewrite README feature list to match current compiler (2026) #48 (README accuracy)