v0.4.0

Added

• Cancelling a run is now handled explicitly (AG-UI has no server-side
  cancel route — the client aborts the streaming request and the server
  observes the disconnect). The view's event stream is wrapped in a
  teardown-aware guard that, on CancelledError/GeneratorExit:

  • guarantees provider teardown — the innermost event generator (whose
    context manager owns the model provider's streaming request) is closed
    explicitly rather than left to garbage-collection order, so no orphaned
    upstream generation keeps billing after the client stopped listening;
  • persists the partial exchange — with a non-null
    CONVERSATION_STORE, the truncated conversation (client history plus
    the assistant text and completed tool calls streamed so far, dropping
    partially streamed tool calls) is saved with the same thread/owner
    scoping as a completed run;
  • audits the cancellation — the configured AuditLogger receives a
    run-level AuditEvent with tool_name="agent.run", success=False,
    and an error starting with "cancelled:", riding the existing
    record() surface so custom loggers keep working unchanged;
  • re-raises the cancellation — persist/audit failures are logged,
    never substituted for the CancelledError.

  No new settings and no new endpoint: cancellation stays transport-level,
  and partial persistence follows the store you already configured.