fix(astro-engine): ensure clientDirectives is defined

[oliverlynch]

withastro/astro#13858 (Merged in Astro 5.8.1) breaks bookshop live as validateComponentProps now expects SSRResult.clientDirectives to be defined, preventing rendering and causing the following warning in the editor:

Error rendering bookshop component Page TypeError: can't access property "keys", clientDirectives is undefined
This is expected in certain cases, and may not be an issue, especially when deleting or re-ordering components.

[Tate-CC]

Thanks for the PR Oliver! I've just request one change. It looks like the clientDirectives object is used to validate the different kinds of directive you're allowed to use. So to support islands in bookshop components we need to include the full list of them (except for client:only which is special).

[oliverlynch]

Looks good to me! Tested the patch with one of my sites on cloudcannon and the live editor works again. I haven't tested if this affects server islands, as I don't have a site setup which uses those (yet?).