COST-002 — Link isolated staging to the club free trial and verify cost alerts #693

Outcome

Link only run-mprc-staging to the existing club-owned Google Cloud Free Trial billing account, with a separately verified gross-usage warning budget. Do not upgrade the account to paid, link production, enable runtime APIs, deploy Functions, or change member data.

Owner direction: Dave Liu started the trial under runmprc@gmail.com and requested continued Firebase backend setup with minimal cost and complexity. Current Console evidence on 2026-10-11 shows Free Trial, $300 unused, expiry January 10, 2027. A separate read-only check sees one open club-accessible billing account; staging and production remain unlinked. Exact financial identifiers remain private.

Officer impact: The isolated engineering staging project can use the trial for later reviewed backend work, with early cost warnings. This does not make member registration, payments, refunds or any production feature available.
Officer documentation: Update docs/officers/LOW_COST_COMMUNITY.md and relevant current-state engineering/officer references after provider readback; keep historical checkpoints dated and intact.
Deployment evidence: None. This outcome changes billing metadata and notification settings only. Website, Functions, Auth, Firestore records, Stripe, DNS, production billing and production behavior must remain unchanged.

Invariants and allowed actions

• Account is exactly runmprc@gmail.com; target is exactly run-mprc-staging.
• Use only the existing account that is linked to the verified trial project. Stop if account selection is ambiguous or the visible account is paid rather than Free Trial.
• Allow the Cloud Billing Budget API only in staging if needed; no Functions, Cloud Build, Artifact Registry or other runtime API enablement.
• Create or reuse one staging-scoped monthly USD10 alerts-only budget, thresholds 50%, 90%, 100%, excluding credits so the trial cannot hide gross usage. Keep existing default billing IAM recipients; do not add access, external recipients or Pub/Sub automation.
• A budget is not a spending cap or approval for ongoing club expenditure. No spend-cap shutdown automation or paid upgrade is included.
• Never print or put billing IDs, private URLs, tokens, account/payment details or member data in public evidence.
• Linking billing does not authorize deployment under CI-001D — Prove backend-first staging and deploy the profile repair #136; BACKEND-001 — Audit the Firebase cutover and approve legacy data disposition #113/CI-001C — Configure protected short-lived Firebase deployment identity #133 and the protected release evidence remain separate gates.

Acceptance

• Revalidate the exact existing club trial account and staging baseline before mutation.
• Budget API enabled only if necessary; no runtime API enabled.
• One staging-scoped monthly USD10 gross-usage warning budget is read back, with three exact thresholds and default recipients enabled.
• Staging billing reads enabled and matches the verified existing trial account.
• Production remains unlinked, and pre/post enabled staging API sets differ only by the explicitly allowed Budget API.
• No Functions/website/provider payment configuration or data deployment occurred.
• Officer/engineering handoff records current state, trial expiry, budget limits, named financial owner, and separate release prerequisites.

Failure and undo

Stop on trial/account mismatch, denied authority, unexpected services or an ambiguous existing budget. If notification setup fails, do not deploy or enable runtime APIs; report the exact bounded failure and leave live commerce disabled. Reverting a billing link or disabling an API requires checking for newly dependent resources first; do not improvise a whole-project shutdown. No production rollback is applicable because production is out of scope.

Claim

Post and read back a timestamped claim before provider mutation. Keep sensitive provider evidence out of GitHub. This issue is a bounded cost prerequisite under #136/#105, not completion of those parent releases.