feat: Armarium full customization and 4-language i18n (v0.8.0)

Replaces Astro Rocket demo content with Armarium branding and adds
complete DE/FR/IT/EN translations across all pages.

Branding & content (v0.7.0):
- Add horizontal SVG logo to navbar with currentColor dark mode support
- Rewrite homepage with Armarium hero, 6 feature cards, trust bar,
  Zürich coat of arms SVG, and CTA; shared HomePage.astro component
- Add privacy page (/datenschutz) with 6 Infomaniak certification cards
  and 8-section policy (ISO 27001:2022, Swiss Hosting, nDSG/GDPR, etc.)
- Add legal notice page (/impressum)
- Rewrite about, contact, 404 pages with Armarium content
- Add features page (/projects) from projects content collection
- Add language switcher dropdown (LanguageSwitcherDropdown.astro)
- Add single launch blog post; remove all demo blog/project content
- Set up i18n foundation: astro.config.mjs, ui.ts, utils.ts

Full i18n (v0.8.0):
- Add all pages in FR/IT/EN: about, contact, blog, features, privacy,
  legal notice — 28 locale variants total
- Language switcher visible in every layout (PageLayout, BlogLayout,
  ProjectLayout, LandingLayout) with translated nav items
- Locale-aware nav and footer hrefs via nav.*.href keys in ui.ts
- Shared page components (AboutPage, ContactPage, FeaturesIndexPage,
  BlogIndexPage) accept locale prop; locale pages are 4-line wrappers
- Extend content.config.ts locale enum with de and it

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/impressum.astro

@@ -0,0 +1,73 @@
+---
+/**
+ * Impressum
+ * URL: /impressum
+ */
+import PageLayout from '@/layouts/PageLayout.astro';
+import Badge from '@/components/ui/data-display/Badge/Badge.astro';
+import Icon from '@/components/ui/primitives/Icon/Icon.astro';
+import { Hero } from '@/components/hero';
+---
+
+<PageLayout
+  title="Impressum — Armarium"
+  description="Impressum der Armarium Suite."
+  noindex
+  locale="de"
+>
+  <Hero layout="centered" size="sm">
+    <Badge slot="badge" variant="brand" pill>
+      <Icon name="file-text" size="sm" />
+      Impressum
+    </Badge>
+    <h1 slot="title">Impressum</h1>
+  </Hero>
+
+  <section class="py-[var(--space-section-md)] bg-background border-t border-border">
+    <div class="mx-auto max-w-2xl px-6 space-y-8 text-foreground-muted" data-reveal>
+
+      <div>
+        <h2 class="font-display text-lg font-bold text-foreground mb-2">Betreiber</h2>
+        <p>Armarium<br />Zürich, Schweiz</p>
+      </div>
+
+      <div>
+        <h2 class="font-display text-lg font-bold text-foreground mb-2">Kontakt</h2>
+        <p>
+          E-Mail:
+          <a href="mailto:hallo@armarium.ch" class="text-brand-500 hover:text-brand-600 transition-colors">
+            hallo@armarium.ch
+          </a>
+        </p>
+      </div>
+
+      <div>
+        <h2 class="font-display text-lg font-bold text-foreground mb-2">Hosting</h2>
+        <p>
+          Infomaniak Network SA<br />
+          Rue Eugène-Marziano 25, 1227 Genf, Schweiz<br />
+          <a href="https://www.infomaniak.com" target="_blank" rel="noopener noreferrer" class="text-brand-500 hover:text-brand-600 transition-colors">
+            www.infomaniak.com
+          </a>
+        </p>
+      </div>
+
+      <div>
+        <h2 class="font-display text-lg font-bold text-foreground mb-2">Haftungsausschluss</h2>
+        <p class="leading-relaxed">
+          Trotz sorgfältiger inhaltlicher Kontrolle übernehmen wir keine Haftung für die Inhalte externer Links. Für den Inhalt verlinkter Seiten sind ausschliesslich deren Betreiber verantwortlich.
+        </p>
+      </div>
+
+      <div>
+        <h2 class="font-display text-lg font-bold text-foreground mb-2">Urheberrecht</h2>
+        <p class="leading-relaxed">
+          Alle Inhalte dieser Website sind urheberrechtlich geschützt. Eine Verwendung ohne ausdrückliche schriftliche Genehmigung ist untersagt.
+        </p>
+      </div>
+
+      <p class="text-sm">Stand: April 2026</p>
+
+    </div>
+  </section>
+</PageLayout>