Maps ONE parsed browser_* tool-call args object to its normalized
RemoteBrowserAction. Pure + synchronous so it can be unit-tested in isolation from
the GraphQL round-trip. Validates required args and throws RemoteBrowserToolArgError
with a model-readable message when they're missing/invalid; unknown tool names also throw.
Maps ONE parsed
browser_*tool-call args object to its normalized RemoteBrowserAction. Pure + synchronous so it can be unit-tested in isolation from the GraphQL round-trip. Validates required args and throws RemoteBrowserToolArgError with a model-readable message when they're missing/invalid; unknown tool names also throw.