CI: THROWSWEB_AOT_LINK_GATE opt-in wiring audit in ci-local llvm tail

[PurHur]

Problem

#2101 tracks the full 007 AOT gate ladder; #2143 adds ExamplesCompileTest::test007ThrowsWebAotLink. On master, ci_run_aot_link_phpunit already honors THROWSWEB_AOT_LINK_GATE, but there is no dedicated opt-in issue documenting the llvm-tail placement, doctor rows, and default-on follow-up (#2135) — unlike 006 (#2011 opt-in → default) or compiler_driver (#2137).

Contributors enabling THROWSWEB_AOT_LINK_GATE=1 manually may miss that execute still requires #2157 before #2135 flips both gates.

Goal

1. Document llvm-tail order in docs/local-ci-matrix.md (link → execute groups; mirror 006 table)
2. Ensure lib/Doctor.php --gates prints link/execute defaults and blockers (DevEx: phpc doctor --gates — 007 ThrowsWeb ladder rows #2102 companion)
3. Add test/unit/CiScriptsTest.php assertion that ci-local.sh calls ci_run_aot_link_phpunit before ci_run_throws_web_aot_execute
4. Close this issue when audit PR lands; CI: Default THROWSWEB_AOT_LINK_GATE + THROWSWEB_AOT_SMOKE_GATE in ci-local after #2101 #2135 remains the default-on flip after Language: AOT throw/catch with user-defined class (007 ValidationError execute) #2157 ✅

Acceptance criteria

THROWSWEB_AOT_LINK_GATE=1 ./script/docker-exec.sh -- bash -lc \
  'source script/php-env.sh && vendor/bin/phpunit --filter test007ThrowsWebAotLink'
# skips or passes per LLVM; must not skip because ci-local forgot wiring

./phpc doctor --gates | grep -i throwsweb
# shows link=0 execute=0 defaults and #2157 blocker note

Dependencies

• Language: AOT throw/catch with user-defined class (007 ValidationError execute) #2157 — AOT throw/catch + ValidationError (execute blocker)
• Testing: ExamplesCompileTest test007ThrowsWebAotLink (007-ThrowsWeb) #2143 — PHPUnit link test
• CI: Default THROWSWEB_AOT_LINK_GATE + THROWSWEB_AOT_SMOKE_GATE in ci-local after #2101 #2135 — default-on flip (separate)

Links

• Testing: THROWSWEB_AOT_LINK_GATE + THROWSWEB_AOT_SMOKE_GATE (007-ThrowsWeb) #2101 · Testing: examples-aot-smoke.sh 007 slice (EXAMPLES_AOT_SMOKE_ONLY=007) #2104 · ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78
• Local CI: ./script/ci-local.sh, make test-harness (Test Compiling Speed #436 ✅)

[PurHur]

Audit-only sibling of #2135 (default-on flip). Do not duplicate implementation work.

Checklist: script/ci-local.sh llvm tail invokes ThrowsWebAot* tests when opt-in gates set; phpc doctor --gates lists 007 AOT stages; docs match #2101 / #2157 state.

Blocked on #2157 execute green. Harness verify: ./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && THROWSWEB_AOT_LINK_GATE=1 vendor/bin/phpunit --filter ThrowsWebAot'.