Edit: This flag is now not-experimental but still opt-in. The DTD URI tool provided by Dart-Code does not require the flag to be set.

Currently the MCP server registration is behind an undocumented flag ("dart.experimentalMcpServer": true) and if that flag is set, we will assume it's available for anything >= 3.9.0-0.

When the MCP server is considered ready to ship, we should change this to not require the experimental flag for that version (but probably still allow it to be set for versions between 3.9.0-0 and whatever the release version is to avoid breaking anyone still using pre-release/beta).

@jakemac53 can you let me know when you're happy for this to be done (and confirm the version number we shouldn't require the flag for).