Unified Conversation Sending for AI and Human Inputs

Established a unified conversation-sending foundation so that both human chat input and AI-originated messages can use the same processing path.

Previously, the flow was centered primarily around UI-driven interaction. By unifying the send path, AscenderAI can now evolve toward a structure where AI and other future input sources can use the same Conversation Runtime.

This avoids maintaining separate conversation engines for humans and AI, while still allowing each source to add its own required processing around a shared conversation foundation.