Umbrella: AdCP 3.1 schema bump — checklist of SDK-side adoptions

[bokelley]

Single tracker for the SDK-side work that becomes actionable when AdCP 3.1 lands. Replaces the previous fan-out of one issue per upstream PR.

Trigger

When adcontextprotocol/adcp cuts the 3.1.0 release. Bump schemas/cache/3.1.0/ via npm run sync-schemas and pin ADCP_VERSION in src/lib/version.ts.

Checklist

Mechanical / schema-cache:

• Bump schemas/cache/ from 3.0.0 → 3.1.0 (was chore(schemas): bump cache from 3.0.0 to 3.1.0 once upstream releases #984)
• Migrate sales_guaranteed storyboard fixture to task_completion.media_buy_id capture path (was fixture: migrate sales_guaranteed storyboard to task_completion.media_buy_id capture path (upstream) #1500 — SDK-side already shipped, remaining piece is upstream fixture)
• Wire output_only flag on format.assets[] — four call sites (was Track upstream adcp#4021: output_only flag on format.assets[] #1525, upstream adcp#4021)
• Document task_completion. prefix syntax in storyboard schema yaml (was Storyboard schema docs: document task_completion. prefix syntax (follow-up to #1417) #1432 — upstream edit)
• Link mock-server to normative-status anchor once adcp#4029 lands (track: link to mock-server normative-status anchor once adcp#4029 lands #1524)

Spec-pending behavior changes (each is its own existing issue, kept open until upstream lands):

• SI cleanup: drop workarounds when adcp#3961 + adcp#3981 land #1481 — SI cleanup when adcp#3961 + adcp#3981 land
• Migrate from 3.0.5 details.status placeholder to AGENT_SUSPENDED / AGENT_BLOCKED codes (3.1 consolidation) #1406 — AGENT_SUSPENDED / AGENT_BLOCKED migration
• feat(server): BuyerAgentRegistry Phase 2 — wire billing-capability enforcement (AdCP 3.1) #1292 — BuyerAgentRegistry Phase 2 billing-capability enforcement
• Adopt AUTH_MISSING / AUTH_INVALID once adcp#3730 lands — split AUTH_REQUIRED handling #1193 — AUTH_MISSING / AUTH_INVALID split (adcp#3730)
• track: implement principal-mode-conditional comply visibility once adcp#3986 lands #1521 — principal-mode-conditional comply visibility (adcp#3986)
• track: wire denial-path conformance once adcp#4028 storyboard lands #1522 — denial-path conformance wire-up (adcp#4028)
• Track upstream adcp#4015: audio variant phase for creative_template storyboard #1523 — audio variant phase for creative_template storyboard (adcp#4015)
• Mock-server fixture scaffolding: per-specialism scenario state machines #1495 — mock-server fixture state machines

Why one umbrella

Five separate trackers all said the same thing ("flip switch when 3.1 lands"). Merging them into a single checklist reduces queue noise and makes the 3.1 cutover a single PR with a single review.

Refs

Closes #984, #1500, #1525, #1432 by absorption.