[scanner] site-rollback runbook claims sync failures fall back to committed content; prebuild is strict and fails the build #493

Summary

runbooks/site-rollback.md step 3 ("Decide whether the cause is site code … or content synced at build time") states:

The prebuild script falls back to committed content when a sync is unavailable, so a sync failure alone does not fail the build.

That is no longer how prebuild behaves. scripts/run-sync-step.ts (which wraps every sync step in package.json prebuild) propagates a non-zero exit and fails the build unless DOCS_SYNC_OPTIONAL=1 is set — and README.md ("How content is sourced") documents exactly that: "If a sync source is unreachable at build time, the build fails so stale content is never deployed silently … CI and Netlify always use the strict behavior. Only the meeting-recordings refresh always falls back to its committed data."

Why it matters

The runbook is the document an operator reads during a broken deploy. As written it tells them to rule out sync failures as a cause of a failed Netlify build, which is the opposite of the current behaviour: an unreachable hivecommons/hive (or any sibling repo) at build time is now a direct cause of a red deploy. That sends triage in the wrong direction at the worst moment.

The same sentence's project list (hive, hotshot, pluk, rationguard, promptargs, dibs) also omits Crux (#490) and Spektacular.

Evidence

• runbooks/site-rollback.md lines 11-14 (main @ 03219a8)
• scripts/run-sync-step.ts header comment + runSyncStep: "Failures fail the build unless DOCS_SYNC_OPTIONAL=1 is set"
• README.md "How content is sourced", last paragraph
• package.json prebuild: every sync runs through scripts/run-sync-step.ts

Proposed fix

Rewrite step 3 to match run-sync-step.ts: a sync failure does fail the build (so a red deploy may be caused by an unreachable project repo, not only by site code); only the meeting-recordings refresh falls back to committed data; DOCS_SYNC_OPTIONAL=1 is local-only. Update the project list to include Crux and Spektacular (or point at the README list to avoid a second copy). Single-file docs change, no code.

— hive: agent=scanner backend=copilot model=claude-fable-5.1 copilot=1.0.88