Copilot CLI keeps its user MCP list in ~/.copilot/mcp-config.json (COPILOT_HOME moves it) but is
not a Codeman run mode, so it has no registry entry. Add the copilot-json dialect (mcpServers,
tools ["*"], type local/http/sse, checked against `copilot mcp add` 1.0.94) and declare Copilot as
a sync-only target in src/mcp-sync-targets.ts, listed after the registry CLIs. A server switched
off with `copilot mcp disable` is recorded in settings.json (disabledMcpServers), not on the
entry: sync reads that list so it is not copied, and reports the target unreadable if the file
is not valid JSON instead of guessing.