feat(pose_3d): workspace check client-side (ghost verde/rosso) + SHOULDER da URDF

web/index.html

@@ -507,6 +507,7 @@
           <label>P <input id="p3P" type="number" step="1" /> °</label>
           <label>W <input id="p3W" type="number" step="1" /> °</label>
         </div>
+        <div id="p3Feasibility" class="p3-feasibility"></div>
         <div class="p3-status" id="p3Status">— polso fermo</div>
         <div class="p3-row" id="p3EditorActions">
           <button id="p3ApplyBtn">Applica (Editor)</button>