v0.50.0

Added

• tools/audit_mcp_surface.py checks the registered MCP tools/resources against
  docs/mcp.md and pins the documented adapter, authentication, and
  optional-dependency boundaries in the local validation gate.
• tools/check_release_claim_hygiene.py checks changelog and release-note prose
  for agent-authorship, self-awarded quality labels, and unsupported
  conformance or certification claims.
• tools/check_commercial_claim_hygiene.py checks commercial docs for the
  AGPL/commercial boundary and for unsupported paid-code-path claims.