i18n(achievements,admin): drop redundant labels and grammar nits

A few small quality wins bundled together:

- The 1-day achievement descriptions read "for 1 consecutive
  days" / "1 Tage in Folge" — singular/plural mismatch that
  was awkward in both languages. Hand-tuned the five 1-day
  variants to "for 1 day" / "an einem Tag"; 7d / 30d copies
  unchanged.
- The two "Two hundred …" / "Zweihundert …" badges now use
  the numeral 200 to match every other count-based badge.
- /admin/integrations toggle rows ("Umami" / "GlitchTip" lines
  that duplicated the card header) drop the literal product
  name and just show the action: the existing
  `umamiEnabled` / `glitchtipEnabled` description copy is
  promoted to the toggle's primary label. SettingsToggle's
  description prop becomes optional to support that.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/admin/_shared.tsx

@@ -179,7 +179,7 @@ export function SettingsToggle({
   disabled,
 }: {
   label: string;
-  description: string;
+  description?: string;
   icon?: React.ComponentType<{ className?: string }>;
   checked: boolean;
   onCheckedChange: (checked: boolean) => void;
@@ -191,7 +191,9 @@ export function SettingsToggle({
         {Icon && <Icon className="text-muted-foreground h-4 w-4" />}
         <div>
           <p className="text-sm font-medium">{label}</p>
-          <p className="text-muted-foreground text-xs">{description}</p>
+          {description && (
+            <p className="text-muted-foreground text-xs">{description}</p>
+          )}
         </div>
       </div>
       <Switch

src/components/admin/glitchtip-section.tsx

@@ -92,8 +92,7 @@ export function GlitchtipSection() {
 
       <div className="mt-4 space-y-3">
         <SettingsToggle
-          label="GlitchTip"
-          description={t("admin.glitchtipEnabled")}
+          label={t("admin.glitchtipEnabled")}
           icon={AlertTriangle}
           checked={settings?.glitchtipEnabled ?? false}
           onCheckedChange={(checked) =>

src/components/admin/umami-section.tsx

@@ -95,8 +95,7 @@ export function UmamiSection() {
 
       <div className="mt-4 space-y-3">
         <SettingsToggle
-          label="Umami"
-          description={t("admin.umamiEnabled")}
+          label={t("admin.umamiEnabled")}
           icon={Activity}
           checked={settings?.umamiEnabled ?? false}
           onCheckedChange={(checked) =>