DevEx: miniwebapp-gates stage 4c — probe examples-aot-smoke 003 slice (#683)

[PurHur]

Summary

• Add EXAMPLES_AOT_SMOKE_ONLY=003 to script/examples-aot-smoke.sh with extracted smoke_003_miniwebapp() (skip until AOT: Native user-class object model for phpc build --project #568; scaffold for Testing: MiniWebApp AOT binary CLI execute smoke (tracked in #747, blocked #764) #485).
• Wire stage 4c in script/miniwebapp-gates.sh: probes the 003 slice when LLVM is present and reports pass/skip/fail with stderr tail (same UX as stage 4a).
• Document stages 4a/4c/4b in examples/003-MiniWebApp/README.md; extend unit tests.

Test plan

• ./script/docker-ci-local.sh fast --filter 'MiniWebAppGatesScriptTest|ExamplesAotSmokeScriptTest|CiScriptsTest::testMiniWebAppGatesScriptExists'
• Docker miniwebapp-gates.sh --no-lint shows stage 4c skipped (AOT: Native user-class object model for phpc build --project #568)
• When AOT: Native user-class object model for phpc build --project #568 lands: remove skip in smoke_003_miniwebapp() and stage 4c should go green

Closes #683

Made with Cursor