[FEATURE] Force overwriting MCP Server configuration.

[steve-calvert-glean]

Feature Description

With the addition of the new configure command in #38, we should fast-follow that change with the ability to update your MCP configuration if your authentication credentials change. We could also consider a --force flag to force an update of the configuration.

npx @gleanwork/mcp-server configure --client cursor --token <foo> --domain <bar> --force

We could consider a twofold approach:

1. Using the --force flag. This destructively makes the change immediately.
2. A user confirmation in the terminal, if changes to the config are detected but the --force flag isn't present.