fix(UX): offer registration when BOM opened on untracked document (#56)

Replace the dead-end warning in Silo_BOM with a question dialog that
offers to register the document via Silo_New. If the user accepts and
registration succeeds, the BOM dialog opens seamlessly.

freecad/resources/icons/silo-rollback.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#cba6f7" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+  <!-- Counter-clockwise arrow -->
+  <polyline points="1 4 1 10 7 10" stroke="#f38ba8"/>
+  <path d="M3.51 15a9 9 0 1 0 2.13-9.36L1 10" stroke="#cba6f7"/>
+  <!-- Clock hands -->
+  <line x1="12" y1="7" x2="12" y2="12" stroke="#89dceb" stroke-width="1.5"/>
+  <line x1="12" y1="12" x2="15" y2="14" stroke="#89dceb" stroke-width="1.5"/>
+</svg>

freecad/resources/icons/silo-status.svg

@@ -0,0 +1,7 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#cba6f7" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+  <!-- Shield shape -->
+  <path d="M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z" fill="#313244"/>
+  <!-- Status bars -->
+  <line x1="8" y1="10" x2="16" y2="10" stroke="#a6e3a1" stroke-width="1.5"/>
+  <line x1="8" y1="14" x2="13" y2="14" stroke="#89dceb" stroke-width="1.5"/>
+</svg>

freecad/resources/icons/silo-tag.svg

@@ -0,0 +1,6 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="#cba6f7" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
+  <!-- Tag shape -->
+  <path d="M20.59 13.41l-7.17 7.17a2 2 0 0 1-2.83 0L2 12V2h10l8.59 8.59a2 2 0 0 1 0 2.82z" fill="#313244"/>
+  <!-- Tag hole -->
+  <circle cx="7" cy="7" r="1.5" fill="#cba6f7" stroke="none"/>
+</svg>

freecad/silo_commands.py

@@ -1998,15 +1998,18 @@ class Silo_BOM:
 
         obj = get_tracked_object(doc)
         if not obj:
-            FreeCAD.Console.PrintError("No tracked Silo item in active document.\n")
-            from PySide import QtGui as _qg
-
-            _qg.QMessageBox.warning(
+            reply = QtGui.QMessageBox.question(
                 None,
                 "BOM",
-                "This document is not registered with Silo.\nUse Silo > New to register it first.",
+                "This document is not registered with Silo.\n\nRegister it now?",
+                QtGui.QMessageBox.Yes | QtGui.QMessageBox.No,
             )
-            return
+            if reply != QtGui.QMessageBox.Yes:
+                return
+            FreeCADGui.runCommand("Silo_New")
+            obj = get_tracked_object(doc)
+            if not obj:
+                return
 
         part_number = obj.SiloPartNumber