@spec all_known_actions() :: MapSet.t(String.t())

All action keys known across the protocol family — including the legacy v0.8 keys, which this implementation lists (so the "action not supported in this version" error stays faithful to the reference) but does not implement.

@spec get_adapter(String.t()) :: {:ok, module()} | {:error, A2UICore.Error.t()}

Resolves the adapter module for a version designator.

Accepts v0.9, 0.9, v0.9.1, v1.0, 1.0, v1_0 … via canonicalization. Returns {:ok, module} or {:error, error} (category :validation) for unsupported versions such as v0.8 or v99.0.

@spec resolve_from_payload(term()) :: {:ok, module()} | {:error, A2UICore.Error.t()}

Resolves the adapter directly from a raw payload (a message map, a list of messages, or a {"messages": [...]} wrapper).

Sniffing order (faithful to the reference):

1. non-list/map payloads are rejected (invalid_payload_type),
2. an empty list is rejected (empty_payload),
3. {"messages": [...]} wrappers recurse into the list,
4. lists resolve via their first item,
5. the item must be a map (invalid_payload_type),
6. a string version resolves the adapter (type_mismatch when present but not a string); a missing version falls back to the legacy v0.8 action keys — which this implementation reports as unsupported — and otherwise fails with missing_field.

All failures carry a detail at path messages.{index}.version.