fix: migrate to tailwind v4 and TS6, add oauth2 dashboard_host setting

- migrate Tailwind v3->v4 (postcss @tailwindcss/postcss, CSS-first @theme/@plugin/@custom-variant)
- fix TS6 build: ignoreDeprecations for baseUrl, react-day-picker v10 classNames, test type fixes
- add dashboard_host setting field with i18n

src/routes/settings.tsx

@@ -45,6 +45,7 @@ const settingFormSchema = z.object({
     language: z.string().min(2),
     user_template: z.string().min(1),
     install_host: asOptionalField(z.string()),
+    dashboard_host: asOptionalField(z.string()),
     reserved_hosts: asOptionalField(z.string()),
     custom_code: asOptionalField(z.string()),
     custom_code_dashboard: asOptionalField(z.string()),
@@ -298,6 +299,20 @@ export default function SettingsPage() {
                                 </FormItem>
                             )}
                         />
+                        <FormField
+                            control={form.control}
+                            name="dashboard_host"
+                            render={({ field }) => (
+                                <FormItem>
+                                    <FormLabel>{t("DashboardHost")}</FormLabel>
+                                    <FormControl>
+                                        <Input {...field} />
+                                    </FormControl>
+                                    <FormDescription>{t("DashboardHostHint")}</FormDescription>
+                                    <FormMessage />
+                                </FormItem>
+                            )}
+                        />
                         <FormField
                             control={form.control}
                             name="reserved_hosts"