Swiss AI Hub v0.292.3

Fixed

• 🐛 Resolved a race condition that could cause agent output streaming chunks to be dropped, leading to incomplete or
  blank answers in chat clients. This fix ensures all DisplayEvents are processed before consumer teardown.
• 🔗 Guaranteed the delivery of complete agent answers by implementing a durable backstop that reconciles any missing
  content from the final stop event, preventing empty assistant turns and associated errors.

Added

• ✨ Introduced shared utility methods, iter_streamed_display_events and wait_for_stop_then_drain, in
  ChatService to ensure all display events are gracefully drained and processed after an agent run completes.
• 📄 Documented the architectural decision for robust streaming in a new ADR: "Drain Display-Event Streams Before
  Consumer Teardown".
• 🧪 Added new unit tests to validate the correctness and resilience of the event draining and answer reconciliation
  logic.

Changed

• 🔄 Refactored all streaming event consumers (including OpenAI SSE, JSON, and native event streams) to utilize the
  new graceful draining mechanisms, improving the consistency and reliability of agent output.
• 🚀 Updated final content resolution for OpenAI and JSON responses to include delta reconciliation, using the
  terminal StopEvent as a source of truth to complete partially streamed or lost answers.