v1.2.7: Phase 0 — CSS foundation + icons + snackbar

style.css: +93 lines — sidebar, view, tabs, toolbar, field (label on top),
  skeleton, snackbar, combobox classes. Font scale 13/14/16.
icons.js (NEW): 10 inline-SVG Lucide icons (play, edit, trash, check, x,
  chevronDown, search, plus, rotateCw, cloud). stroke=currentColor.
snackbar.js (NEW): showSnackbar(msg, type). bottom-right, 4s/8s auto-hide,
  stacking max 4, accessibility role=status aria-live=polite.
index.html: include icons.js before utils.js

site/templates/index.html

@@ -151,6 +151,7 @@ window.APP = {
   firstServiceId: {{ (config.service_ids[0] if config.service_ids else 1) | tojson }}
 };
 </script>
+<script src="{{ url_for('static', filename='js/icons.js') }}"></script>
 <script src="{{ url_for('static', filename='js/utils.js') }}"></script>
 <script src="{{ url_for('static', filename='js/params-render.js') }}"></script>
 <script src="{{ url_for('static', filename='js/instances.js') }}"></script>