Returns the default values for all Conversation fields.

Required fields (per Mastodon OpenAPI spec):

• id: Local database ID of the conversation
• accounts: Participants in the conversation
• unread: Is the conversation currently marked as unread?

Optional fields:

• last_status: The most recent status in the conversation

Returns a new Conversation map with default values. Can optionally merge custom values via the overrides parameter.

Examples

iex> Conversation.new(%{"id" => "123", "accounts" => [account]})
%{"id" => "123", "accounts" => [account], "unread" => false, ...}

List of required fields per the Mastodon OpenAPI specification.

Validates that all required fields are present and non-nil. Returns {:ok, conversation} or {:error, {:missing_fields, fields}}.