docs: correct merge queue admission command

[anchenqlw]

Summary

• replace queue admission through Auto-merge-dependent gh pr merge with GraphQL enqueuePullRequest
• bind every queue mutation to the reviewed head through expectedHeadOid
• make network-indeterminate mutations safe with preflight and unconditional post-readback
• verify the exact merge-group run and its dco, preview, and validate jobs
• record the live PR [AI Translation][zh-CN → en-US] Let an Agent Click Through Your Product From Start to Finish #11 acceptance evidence and preserve disabled Auto-merge

Validation

• git diff --check
• six guarded Bash examples pass syntax checks
• npm run check
• live GraphQL schema and PR [AI Translation][zh-CN → en-US] Let an Agent Click Through Your Product From Start to Finish #11 queue acceptance

Signed-off-by: 安陈 anchen.qlw@alibaba-inc.com