v0.1.3

Fixes MCP-server discovery. 0.1.2 shipped a .mcp/server.json using an outdated schema, which NuGet rejected as invalid ("server.json file is invalid") — so it wasn't a usable MCP server on NuGet or in Visual Studio. 0.1.3 rewrites the manifest to the current 2025-10-17 schema (registryType/identifier, transport: stdio, top-level version), so TestAtlas.Mcp is now a valid, discoverable MCP server. No CLI changes since 0.1.2.