docs(releases): correct 31 claims the 17.7.0 fact-check pass found

A second pass over every cited sha, PR number, key name and behavioural
claim on the 17.7.0 page, against each changeset. Among the corrections:
element:text variant is an advisory component-props finding, not a parse
refusal; the missing-table exit 1 of the one-shot previews was superseded
in the same release by empty work and exit 0; the cloud AI runtime never
read agent.lifecycle; #21464 has nine stages, not eleven; and a job body's
write of the stored-metadata tables is not covered by #21563.

Claude-Session: https://claude.ai/code/session_016tKoy8NJa35Yih1FdzrVmn
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude