feat(v3-ref-seller): implement 4 spec-required sales-* methods (get_media_buys, provide_performance_feedback, list_creative_formats, list_creatives)

[bokelley]

Context

The v3 reference seller declares specialisms=("sales-non-guaranteed",) in its DecisioningCapabilities, but is missing four methods that the sales-non-guaranteed specialism contract requires. In v6.0 rc.1 validate_platform() will reject these adopters at boot.

Refs:

• examples/v3_reference_seller/src/platform.py
• src/adcp/decisioning/specialisms/sales.py:184-227 (specialism contract)

Missing methods

1. get_media_buys — list media buys scoped to the dispatching buyer/principal. Returns the spec get-media-buys-response shape.
2. provide_performance_feedback — accept buyer-side performance signals attached to a media buy or package. Persist for downstream optimization. Returns the spec provide-performance-feedback-response shape.
3. list_creative_formats — return the formats the seller supports (with channel + dimensions + asset slots). Returns the spec list-creative-formats-response shape.
4. list_creatives — list previously-synced creatives for the dispatching principal, with filtering. Returns the spec list-creatives-response shape.

Acceptance Criteria

• All 4 methods implemented in examples/v3_reference_seller/src/platform.py
• Persist to existing or new ORM tables (no in-memory only)
• Return spec-shaped responses validated against the AdCP JSON schemas
• Smoke tests (or storyboard runs) cover each new method
• validate_platform() passes with specialisms=("sales-non-guaranteed",)

[bokelley]

Triage

Classification: Feature request
Bucket(s): examples
Status: drafting-pr
Milestone: (omitted — no target version specified in issue)

What the experts said:

• dx-expert: Execute — well-scoped; flagged silent-skip in get_media_buys (add logger.warning) and stale-stub concern for list_creatives (acceptable as deferred)
• code-reviewer: Approved — no blockers; one stale "five"→"six" docstring nit fixed before opening; IntegrityError pattern consistent with existing MediaBuy approach

My take: All four methods are implementable against existing types and the MediaBuy ORM table. get_media_buys queries the existing table; provide_performance_feedback gets a new idempotency-keyed PerformanceFeedback table; list_creative_formats and list_creatives are stubs — the latter defers sync_creatives persistence wiring to a follow-up.

Drafted PR: #394

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Triaged by Claude Code. Session: https://claude.ai/code/session_01R5JrFxdiswxFhwvEr3SWAd

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Generated by Claude Code