Publishes an awareness state for a server-side participant, such as an agent or tool. The process subscribes to a document and keeps one client id for its lifetime.

Awareness is Yjs's term for ephemeral participant state. To inspect and authorize client awareness messages, use the Slap.Yjs.Awareness codec. The process claims its id before publishing. Local client claims cannot take it over; remote awareness conflicts remain possible.

{:ok, presence} =
  Slap.Yjs.Presence.start_link(
    module: MyApp.DocServer,
    doc_id: {"my-service", "doc-1"},
    state: %{"user" => %{"name" => "Assistant"}}
  )

:ok =
  Slap.Yjs.Presence.update(presence, %{
    "user" => %{"name" => "Assistant"},
    "busy" => true
  })

The process republishes its state every :renew_every milliseconds (15,000 by default). y-protocols clients remove a state if its clock does not advance for 30 seconds. If the document server stops, the process rejoins and republishes. Transient rejoin failures are retried after 1 s, backing off to at most 30 s. Updates received while disconnected are published on rejoin. Stopping the presence process removes its state. Deleting the document stops the process without a supervisor restart.

Options:

• :module (required) - the document server module, as for Slap.Yjs.Docs.join/3.
• :doc_id (required) - the document.
• :state (required) - a JSON map with string keys, or fn client_id -> map end. The function runs in the presence process once during startup; rejoining preserves the id and latest state. Nested maps require string keys; strings must be valid UTF-8, and integers must fit in signed 64 bits. Invalid maps raise ArgumentError in the caller. Invalid function results fail startup.
• :owner - a pid to monitor. Its exit stops the presence without a supervisor restart, including while retrying a join. The owner is independent of the process that starts or supervises the presence.
• :renew_every - milliseconds between renewals (default 15,000).
• :docs, :timeout - as for Slap.Yjs.Docs.join/3.
• :name - the process name.