CI: Default SESSIONS_WEB_AOT_LINK_GATE=1 in ci-local after #1946 green

[PurHur]

Problem

#1946 adds ExamplesCompileTest coverage for 005-SessionsWeb AOT link only (phpc build --project / bin/compile.php -l). The env gate SESSIONS_WEB_AOT_LINK_GATE defaults to 0 — full ci-local.sh does not exercise 005 link until contributors opt in.

Execute remains #1891 + runtime (#1938 ✅ closed on master; re-open if regressions).

Goal

After test005SessionsWebAotLink passes on php-compiler:22.04-dev:

1. Default SESSIONS_WEB_AOT_LINK_GATE=1 in script/ci-defaults.env (llvm tail / @group aot-link)
2. Opt-out SESSIONS_WEB_AOT_LINK_GATE=0 for session-runtime-only PRs
3. Document in docs/local-ci-matrix.md; extend phpc doctor --gates (DevEx: phpc doctor --gates lists 005-SessionsWeb ladder (#1887–#1894) #1903)
4. Update examples/README.md run matrix: AOT link ✅ when gate on

Implementation hints

Piece	Path
Test	test/unit/ExamplesCompileTest.php — from #1946
Defaults	script/ci-defaults.env
CI	script/ci-local.sh — PHPUnit filter or existing aot-link group
Skip	LlvmToolchain::isReady() — exit 0 when LLVM missing

Gate ladder (005)

#1946 link (this flip) → #1891 execute → #1921 opt-in AOT smoke → #1923 default-on

Acceptance criteria

SESSIONS_WEB_AOT_LINK_GATE=1 ./script/ci-local.sh --filter test005SessionsWebAotLink
docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  env SESSIONS_WEB_AOT_LINK_GATE=1 ./script/ci-local.sh --filter test005SessionsWebAotLink

No GitHub Actions.

Dependencies

• Testing: ExamplesCompileTest 005-SessionsWeb AOT link (-l) before CGI execute #1946 — link test must exist and pass
• Examples: 005-SessionsWeb — session_start + flash message reference app #1881 ✅ — example tree
• Testing: 005-SessionsWeb AOT link + two-request CGI execute smoke #1891 — execute not required for this issue

Links

• CI: SESSIONS_WEB_AOT_SMOKE_GATE opt-in in ci-local after #1891 lands #1921, CI: Default SESSIONS_WEB_AOT_SMOKE_GATE=1 in ci-local after #1921 green #1923, Testing: 005-SessionsWeb AOT link + two-request CGI execute smoke #1891
• ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78 Phase 4 (005 ladder)

[PurHur]

Closing as superseded: SESSIONS_WEB_AOT_LINK_GATE defaults to 1 in script/ci-defaults.env on master. Remaining 005 ladder work: execute default-on #1923 (SESSIONS_WEB_AOT_SMOKE_GATE still 0), deploy #1974, serve--aot #2333. Canonical CI policy: #436 / local Docker only (#394 ✅).