feat(protocol): adopt AdCP 3.2 beta.9

[bokelley]

Summary

• vendor and verify the signed AdCP 3.2.0-beta.9 schema bundle
• regenerate public models while preserving compatibility aliases and retained reporting-webhook correlation patches
• add end-to-end client, adapter, server, CLI, and simple-API support for list_account_changes
• make schema regeneration deterministic and prevent patch backup artifacts

This release includes upstream adcp#6794.

Validation

• make check-schema-drift
• make typecheck-all
• uv run python scripts/generate_versioned_stubs.py --check
• uv run pytest -q (7,338 passed, 77 skipped, 9 deselected, 1 xfailed)
• pre-commit hooks (Black, Ruff, mypy, Bandit, repository hygiene)

[aao-secretariat]

MUST FIX: list_account_changes maps to domain "account", but its three sibling account operations (list_accounts, sync_accounts, get_account_financials) all map to "media_buy" — and for good reason. "account" is not a valid supported_protocols value: the capabilities schema enum is [media_buy, signals, governance, sponsored_intelligence, creative, brand, measurement] (verified in schemas/cache/3.2.0-beta.9/protocol/get-adcp-capabilities-response.json:871); account management is a separate top-level account capability block, not a protocol.

_detect_domains() feeds these values straight into capabilities_response(domains), so any server that registers list_account_changes and relies on auto-generated capabilities (the documented default) advertises supported_protocols: ["account", ...] on the wire — an out-of-enum value that fails buyer-side validation and the compliance runner. Map it to "media_buy".

Suggested change

	"list_account_changes": "account",
	"list_account_changes": "media_buy",