Untrusted sessions (MCP, the control channel) checked only the top-level command and the steps of
`actions.play`. Any other command that runs commands internally ran them unchecked, so the allowed
`file.automate.conditionalModeChange` could run `image.mode.*`, which the desktop gate denies
because it resolves the user's configured colour profiles.
`Session::dispatch` now applies `Session::authorize` to every command before any side effect,
nested ones included, which closes the class rather than this one command. Sessions without a
gate (local UI, `photocraft-cli run`) are unchanged.
62b0d0bd60