Release b229

Add unit tests for handlers/utils and client/routing modules

• Add 32 unit tests covering:
  • IP extraction from headers
  • Message processing (merge, filter)
  • Think tag removal
  • Stop words merging
  • Max tokens adjustment
  • JSON truncation
  • Prefix application
  • Routing algorithms (deterministic, weighted random)
• Add PartialEq derive to MessageContent and ContentPart for test comparisons
• CI already includes cargo test in check-and-test job