Agent Context v0.5.0: Add opt-in telemetry for conversation classification insights

Agent Insights now includes optional telemetry to help us improve both Agent Context MCP, and also Agent Context Insights itself. You can choose to share metadata only (scores, sentiment, content gaps, token usage) or full conversation content with Sanity for model improvements. All telemetry sharing is disabled by default.

messages parameter in classifyConversation is now required.