v0.2.8: MCP policy foundations

TL;DR

• Granular MCP policy — per-tool blocked_tools and ask_tools controls in policy.yaml.
• Live tool discovery — introspect running MCP servers via the MCP protocol with provenance metadata.
• Security fixes — XSS sanitization, CSRF protection, credential leak prevention, DOM injection fixes, goroutine safety.

Added

• Per-MCP-tool blocked_tools and ask_tools granular controls for tool-level gating within MCP servers
• Live MCP tool discovery via protocol introspection with provenance metadata
• Policy management UI tab with MCP tool matrix and inline config editor

Fixed

• XSS sanitization in web UI output
• CSRF protection on state-changing API endpoints
• Credential leak prevention in API responses and logs
• DOM chip injection — user-controlled values rendered as text nodes
• Goroutine safety — concurrent map access in policy engine