v0.24.0: 0.24.0: notes for the agent, NodeInfo::source (#48)

Added

• Notes for the agent: under oxframe dev, Comment (or C) marks a node
  or an area of the frame at the playhead and takes a note. oxframe check reports open notes first, as review_note errors with the text,
  time, node, file:line and a crop; oxframe notes done <id>
  (with --reply for an answer) closes one (MCP: notes, note_done). See
  https://oxframe.dev/docs/editor#review-notes.
• NodeInfo::source: the file:line of a node's add, in the editor's
  scene tree.

Breaking

• NodeInfo has a new field, source, so code that builds one with a
  struct literal must set it (the wire format is unchanged: the field is
  optional, and the protocol version stays 1).

  // before
  NodeInfo { id, parent, kind, name }
  // after
  NodeInfo { id, parent, kind, name, source: None }