fix: show the chunk-load toast once per page

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

frontend/src/routes/(root)/+layout.svelte

@@ -36,6 +36,8 @@
 		'Importing a module script failed',
 		'Unable to preload CSS'
 	]
+	// One failed component rejects once per chunk and stylesheet it needed.
+	let chunkLoadToastShown = false
 
 	const monacoEditorUnhandledErrors = [
 		'Model not found',
@@ -217,6 +219,8 @@
 				// a component loaded on demand would otherwise silently never appear.
 				if (chunkLoadErrors.some((m) => message.startsWith(m))) {
 					console.warn(message)
+					if (chunkLoadToastShown) return
+					chunkLoadToastShown = true
 					sendUserToast(
 						'Part of the page failed to load, Windmill may have been updated',
 						true,