ui: replace inline state styles with css classes

apps/ui/css/wizard.css

@@ -989,6 +989,17 @@
   border-color: var(--bg-muted);
 }
 
+.btn-back:disabled {
+  opacity: 0.35;
+  cursor: not-allowed;
+}
+
+.btn-back:disabled:hover {
+  background: var(--bg-overlay);
+  color: var(--text-secondary);
+  border-color: var(--border);
+}
+
 .btn-save-draft {
   background: none;
   color: var(--text-muted);
@@ -1044,6 +1055,20 @@
   box-shadow: 0 1px 4px rgba(13, 148, 136, 0.3);
 }
 
+.btn-continue.is-final-step {
+  background: #3fb950;
+  border-color: #2ea043;
+  box-shadow: 0 1px 4px rgba(63, 185, 80, 0.4);
+}
+
+.btn-continue.is-final-step:hover {
+  background: #2ea043;
+  border-color: transparent;
+  box-shadow:
+    0 2px 10px rgba(63, 185, 80, 0.45),
+    0 0 0 3px rgba(63, 185, 80, 0.18);
+}
+
 /* ── Code editor ── */
 .code-block {
   border: 1px solid var(--border);