add api assistants endpoints

[alak]

Adding 2 endpoints to the API:

/api/assistants: A paginated endpoint to list/search across all assistants

/api/user/assistants: A endpoint to list current user's assistants and the ones he already used in the past

[nsarrazin]

Seems to work well in local testing! Do you also need to expose the endpoints for subscribing/creating/editing assistants or can you use the form actions directly?

[coyotte508]

At one point error response between the API endpoints and the hooks.server.ts should be standardized cc @nsarrazin , for now in the hooks the error response looks like this:

	function errorResponse(status: number, message: string) {
		const sendJson =
			event.request.headers.get("accept")?.includes("application/json") ||
			event.request.headers.get("content-type")?.includes("application/json");
		return new Response(sendJson ? JSON.stringify({ error: message }) : message, {
			status,
			headers: {
				"content-type": sendJson ? "application/json" : "text/plain",
			},
		});
	}

It sends {error: ...} instead of {message: ...}

Or we could create a handleError in hooks.server.ts and throw errors in the api endpoints maybe

[alak]

Seems to work well in local testing! Do you also need to expose the endpoints for subscribing/creating/editing assistants or can you use the form actions directly?

Yes that's the next step