hardened password validation, added tests

frontend/src/routes/auth/password/change/[id]/+page.svelte

@@ -41,13 +41,21 @@
 	<form class="content" method="POST" use:enhance={handleChange}>
 		<h1 class="step-title title">{$t('change_password')}</h1>
 		{#if form?.errors}
-			{#each form?.errors as error (error.id)}
+			{#each form.errors as error (error.id)}
 				<h4
 					class="step-subtitle warning"
 					in:receive={{ key: error.id }}
 					out:send={{ key: error.id }}
 				>
-					{$t(error.key)}
+					{$t(error.key, {
+						values: {
+							message:
+								error.field
+									.split(' ')
+									.map((tag) => $t(tag))
+									.join(', ') || ''
+						}
+					})}
 				</h4>
 			{/each}
 		{/if}