fix: close readiness capture surfaces

[auscaster]

Summary

• use Google Cloud's stable public access-bootstrap page instead of its cyclic authentication gateway
• use Notion's official Markdown documentation twin for the create-page evidence surface
• preserve the same semantic roles, scope, entity, and service-use target

Local proof

• 20 vendors / 20 declarations validate
• full-tree r5 planning succeeds
• all 186 exact capture work units complete with zero residue
• no cohort expansion or scoring-policy change