feat(compliance): cover three missing tasks

[bokelley]

Summary

Restores the bounded, reviewable slice from closed PR #4294 on a clean branch based on main:

• search_brands on the existing brand protocol storyboard
• get_creative_features on the existing content-standards storyboard
• get_media_buy_artifacts on the existing content-standards storyboard, with controller-seeded buy state

Each task is gated with step-level requires_tool, so agents that do not advertise an experimental task receive missing_tool rather than failing the whole storyboard. None were added to storyboard-level required_tools.

Verification

• compliance source build passes (41 universal, 6 protocol, 21 specialism storyboards)
• sample-request, response-schema, and validation-path lints pass
• changeset protocol scope passes
• the standalone scoping test could not run in the sparse worktree because server/src/training-agent/task-handlers.ts was not checked out; the compliance build executes the source-tree scoping lint successfully

Part of #4291. Remaining umbrella tracks will be split into focused follow-ups.

[aao-secretariat]

Medium: doc_ref dangles. The get_creative_features doc lives at docs/governance/creative/get_creative_features.mdx → route /governance/creative/get_creative_features. There is no page at /creative/task-reference/get_creative_features — that directory has no get_creative_features.mdx, and no redirect covers it. doc_ref is not build-validated, so the green compliance build does not catch this. A reader following the link in the published compliance asset gets a 404.

Suggested change

	doc_ref: "/creative/task-reference/get_creative_features"
	doc_ref: "/governance/creative/get_creative_features"

[aao-secretariat]

Medium: doc_ref points to a page that does not exist. No search_brands.mdx under docs/brand-protocol/tasks/, and search_brands is not documented anywhere in docs/ (grep returns nothing). The other steps in this storyboard (get_brand_identity) resolve to real pages; this one dangles. Either ship the task doc alongside the storyboard step or point doc_ref at the page that actually documents search_brands. doc_ref is not build-validated, so the compliance build does not flag it.

[aao-secretariat]

Ladon verdict: Approve

Approve — additive compliance coverage restoring three experimental-task storyboard steps (search_brands, get_creative_features, get_media_buy_artifacts).

Checked: sample requests conform to request-schema required fields; validation paths (brands, results, artifacts, media_buy_id) match the response schemas; controller_seeding placement (under prerequisites) and top-level fixtures.media_buys match the established media-buy scenario pattern; changeset is minor, appropriate for additive coverage. No wire-shape drift, no schema↔docs breaking mismatch, no oneOf regression, no released-artifact mutation.

Medium findings

• static/compliance/source/specialisms/content-standards/index.yaml:600 — get_creative_features doc_ref points to a non-existent route
• static/compliance/source/protocols/brand/index.yaml:175 — search_brands doc_ref dangles; task is undocumented

Two medium doc_ref findings, neither in data-loss/schema/infra category, no blocking findings, no gated paths satisfied issue (gated_paths: false), high_risk false, no team gate. Two mediums fall through the decision table to row 9 → approve. Worth a follow-up to wire up the dangling doc_ref links, but not blocking.

Medium findings

• static/compliance/source/specialisms/content-standards/index.yaml:600 — get_creative_features doc_ref points to a non-existent route
• static/compliance/source/protocols/brand/index.yaml:175 — search_brands doc_ref dangles; task is undocumented