Harden Expert Persona builder and add model suggestion.

Build credentials during Phase 1 and streamline human participant setup.

feat: human participant turns + credential intake redesign

feat(transparency): add "View current chat prompts" to settings

feat(participants): add "Select N Automatically" option

feat(limits): expose repetition / failsafe limits in settings menu

Tighten CCAI conversation flow and visual threading

Build CCAI Vibe Demo on top of LLMChats3 baseline