Fixed:
- Generated specs use the stream and identity a model declares on an element
  (#434). An example that names no stream takes its element's declared
  aggregate or swimlane; an identity the model marks (idAttribute), or a
  {Stream}Id / aggregateId field, with no example value is minted once per
  stream and set on every element that leaves it out. On the public corpus,
  identity TODOs go from 110 to 33.

Added:
- EmlangStep.Stream and EmlangStep.Identities, filled by the eventmodelers.ai
  JSON reader.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017DbTkhs3JxSMCWasTzPdRq