approveSandboxPermissions screens untrusted `_meta`, so it takes
`unknown` and decides the shape itself rather than claiming its input is
already an McpUiResourcePermissions — which had forced its own tests to
cast malformed fixtures through `as unknown as`.
Also stop honoring `true` as a permission marker. The spec defines every
permission as an object (`camera: {}`), so `true` was an undocumented
shorthand, and honoring it means a server typo turns an iframe permission
on. Only the object marker grants now; arrays are rejected too.
Signed-off-by: cliffhall <cliff@futurescale.com>
286dd86f6b