ui: mask API Key field in settings and error splash to stop browser a… (#26562)

* ui: mask API Key field in settings and error splash to stop browser autofill

* ui: set autocomplete=new-password on private fields

The password input type makes browsers offer to save the API key
in the password manager and autofill saved site credentials into
the field. The new-password autocomplete value disables both.

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Co-authored-by: Pascal <admin@serveurperso.com>

tools/ui/src/lib/components/app/settings/SettingsChat/SettingsChatFields.svelte

@@ -81,7 +81,8 @@
 				<div class="relative w-full">
 					<Input
 						id={field.key}
-						type={field.isPositiveInteger ? 'number' : 'text'}
+						type={field.isPrivate ? 'password' : field.isPositiveInteger ? 'number' : 'text'}
+						autocomplete={field.isPrivate ? 'new-password' : undefined}
 						{...field.isPositiveInteger
 							? {
 									min: String(field.min ?? 1),