Use mcp instead of fastmcp CLI as command in "mcp install"

[samefarrar]

Currently, when you run mcp install ..., it adds uv run --with fastmcp fastmcp ... to the Claude config file.
We don't need to do this anymore since fastmcp functionality has been merged into the main mcp python SDK.
Instead, we can make mcp install ... run uv run --with mcp mcp ....

Motivation and Context

Running with --with fastmcp fastmcp continues to rely on an unnecessary external dependency when this functionality has been merged into the mcp cli command.

How Has This Been Tested?

I added a test to check that the command added to the Claude config can run (with --help). This does pass with the fastmcp version but requires an additional external dependency.

Breaking Changes

No, even previous installs will still work. All tests continue to pass.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[dsp-ant]

Good catch! Thank you for trying 1.2.0rc1 and finding this!