Set workspace, perspective, and semantic search on the endpoint

Workspace, perspective, and semantic search are now settings on an MCP endpoint's dataset source, so every agent that connects gets the same behavior. Semantic search stays on by default.

Endpoint URLs now use v2026-11-03, which serves the endpoint's configuration only and refuses query parameters such as groqFilter or perspective with 400. URLs on v1 keep working as before, parameters included. To move an agent over, copy the endpoint URL from the Context app and set any parameters it used on the endpoint instead.