feat: redesign Step 8 with flat list layout matching room steps

Replace bordered card sections with flat rows using hairline dividers,
opacity dimming, and native radio controls to match the room step visual
pattern. Also includes structural refactors (step-sections, address-sections)
and running totals bar polish from the modernization branch.

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

languages/siegel-umzugsliste-de_DE.po

@@ -1137,3 +1137,22 @@ msgstr "Mobil (Beladeadresse)"
 #: includes/class-cpt.php
 msgid "Mobile (Unloading)"
 msgstr "Mobil (Entladeadresse)"
+
+#: includes/class-shortcode.php
+#: templates/form-page.php
+msgid "Step"
+msgstr "Schritt"
+
+#: includes/class-shortcode.php
+#: templates/form-page.php
+msgid "of"
+msgstr "von"
+
+#: includes/class-shortcode.php
+#: templates/form-page.php
+msgid "Edit"
+msgstr "Bearbeiten"
+
+#: includes/class-form-renderer.php
+msgid "Montage?"
+msgstr "Montage?"