Docs: examples/README drift guard — assert no stale #764 blocked wording

[PurHur]

Problem

#764 ✅ closed (003 native execute green), but examples/README.md still says execute is blocked (#1531). The same drift can recur after gate flips (#1760) because only human review catches it.

#1802 solved wave-3 doc drift; examples tree has no equivalent guard.

Goal

1. Add script/check-examples-readme-sync.php (or extend an existing checker) that fails when examples/README.md contains known-stale phrases (#764 open, empty stdout, execute blocked, etc.) while MiniWebAppAotExecuteTest is default-on
2. Opt-in gate EXAMPLES_README_SYNC_GATE=1 in ci-fast.sh; default-on after Examples: Sync examples/README.md run matrix after #764 close #1531 lands
3. Wire test/unit/ExamplesReadmeSyncTest.php

Implementation hints

File	Notes
examples/README.md	Canonical matrix — fix in #1531 first
test/unit/ExamplesReadmeTest.php	Today expects stale #764 text — flip with #1791
examples/003-MiniWebApp/README.md	Already green post-#764 — use as truth source
script/ci-common.sh	Mirror ci_run_wave3_roadmap_sync pattern (#1802)

Acceptance criteria

php script/check-examples-readme-sync.php    # exit 0 after #1531
EXAMPLES_README_SYNC_GATE=1 ./script/ci-fast.sh --filter ExamplesReadmeSyncTest

Dependencies

• Examples: Sync examples/README.md run matrix after #764 close #1531 — manual README fix first
• Testing: Flip ExamplesReadmeTest when #1531 updates execute status #1791 — ExamplesReadmeTest flip
• CI: North Star 1 gate-flip bundle — #1530 done; #1523 + #1752 remain before #1044 close #1760 — gate defaults

Links

• ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78 · 🌐 North Star 1: Web-capable PHP application (living tracker) #1044