content: replace scaffolding with bilingual pages and case studies

Ship the final German and English copy, compose every route from shared page primitives, and cover claims, parity and contact briefing in tests.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/shared/contact-briefing/contact-briefing.scss

@@ -0,0 +1,47 @@
+.briefing {
+  max-width: 40rem;
+}
+
+label {
+  font-weight: 600;
+}
+
+.required {
+  color: var(--color-accent-soft);
+  margin-left: var(--space-1);
+}
+
+.hint,
+.incomplete,
+.note {
+  margin: 0;
+  color: var(--color-text-muted);
+  font-size: var(--text-sm);
+}
+
+input,
+select,
+textarea {
+  width: 100%;
+  padding: var(--space-3);
+  border: 1px solid var(--surface-glass-border);
+  border-radius: var(--radius-sm);
+  background: var(--color-surface-raised);
+  color: var(--color-text);
+  font: inherit;
+}
+
+.actions a {
+  color: var(--color-accent-cool);
+  text-decoration: none;
+}
+
+.submit {
+  font-weight: 600;
+}
+
+@media (hover: hover) and (pointer: fine) {
+  .actions a:hover {
+    text-decoration: underline;
+  }
+}