E0304: Can't read an island's props

The compiler reads an imported component's props from its file (defineProps<…>(), a React component's typed props, Svelte's $props()). These props use a TypeScript type with no Go equivalent, or are declared in a way the compiler doesn't follow. Declare the props in Go instead, with a struct marked @ui.Island("path").

Wrong

// Bad.vue: defineProps<{ lookup: Map<string, number> }>()
import Bad "./islands/Bad.vue"

Right

@ui.Island("./islands/Bad.vue")
type Bad struct {
	Lookup map[string]float64 `json:"lookup"`
}