Release v1.1.0: fix examples web smoke regression (001-SimpleWeb serve readiness)

[PurHur]

Context

Daily release review 2026-06-26: ./script/release-readiness.sh --full --json fails examples-web-smoke.sh after quick gates all green.

Prior tracker #9226 closed; web smoke regressed on current master (may be related to #12034 preg JIT / web runtime churn).

Roadmap: #78 user release v1.1.0 gate checklist.

Failure (2026-06-26, Docker harness)

Full bundle:

release-readiness:   FAIL: examples-web-smoke.sh (exit 1)

Standalone repro:

examples-web-smoke: starting (VM)
examples-web-smoke: 001-SimpleWeb on 127.0.0.1:<port> (VM)
examples-web-smoke: server on 127.0.0.1:<port> did not become ready

Acceptance criteria

• ./script/examples-web-smoke.sh exits 0 with final line examples-web-smoke: ok in Docker
• ./script/release-readiness.sh --full --json → examples-web-smoke gate ok

Gate command

./script/docker-exec.sh -- bash -lc './script/examples-web-smoke.sh'
./script/docker-exec.sh -- bash -lc './script/release-readiness.sh --full --json'

Milestone

v1.1.0 user release — blocks tag until --full bundle green.

[PurHur]

claim: worker-lane-b — batch (issues #12040)

[PurHur]

Merged via #12050

Root cause: ServeCompileCache reused compiled Block constants by reference; the second phpc serve request mutated the cached header() literal to "", producing a premature HTTP header terminator and wrong Content-Length (002-StaticWeb GET / truncated).

Fix: clone constant cells per VM run (Block::scopeConstantVariable) + ignore blank queued header lines.

Verification:

• phpunit test/unit/Web/ServeCompileCacheConstantsTest.php — OK
• ./script/examples-web-smoke.sh — examples-web-smoke: ok