Review follow-ups on #2038.
`configModalTarget` is the *source* server in clone mode, so spreading its
settings copied that server's OAuth client secret, metadata, roots and
behavior flags onto a new entry the user had only given a URL and headers.
Only an edit carries the other fields forward now — it has to, since
`settings` replaces the node wholesale — while add and clone build from the
empty settings shape.
Also drops an unnecessary `as unknown as` in the new useServers test
(`mcpServers` already holds `StoredMCPServer`, which types `headers`), and
removes a `settings: null` instruction the parameter's type does not allow.
Signed-off-by: cliffhall <cliff@futurescale.com>
82ce02b516