fix: save Modified attribute and SSE retry reset

- silo_origin.py: use Gui.Document.Modified instead of App.Document.Modified
  (re-applies fix from #13 that was lost in rebase)
- silo_origin.py: add traceback logging to saveDocument error handler
- silo_commands.py: reset SSE retry counter after connections lasting >30s
  so transient disconnects don't permanently kill the listener

freecad/silo_commands.py

@@ -2350,23 +2350,30 @@ class SiloEventListener(QtCore.QThread):
     # -- thread entry -------------------------------------------------------
 
     def run(self):
+        import time
+
         retries = 0
         last_error = ""
         while not self._stop_flag:
+            t0 = time.monotonic()
             try:
                 self._listen()
                 # _listen returns normally only on clean EOF / stop
                 if self._stop_flag:
                     return
-                retries += 1
                 last_error = "connection closed"
             except _SSEUnsupported:
                 self.connection_status.emit("unsupported", 0, "")
                 return
             except Exception as exc:
-                retries += 1
                 last_error = str(exc) or "unknown error"
 
+            # Reset retries if the connection was up for a while
+            elapsed = time.monotonic() - t0
+            if elapsed > 30:
+                retries = 0
+            retries += 1
+
             if retries > self._MAX_RETRIES:
                 self.connection_status.emit("gave_up", retries - 1, last_error)
                 return

freecad/silo_origin.py

@@ -392,12 +392,17 @@ class SiloOrigin:
                 obj.SiloPartNumber, str(file_path), properties, comment=""
             )
 
-            # Clear modified flag
-            doc.Modified = False
+            # Clear modified flag (Modified is on Gui.Document, not App.Document)
+            gui_doc = FreeCADGui.getDocument(doc.Name)
+            if gui_doc:
+                gui_doc.Modified = False
 
             return True
         except Exception as e:
+            import traceback
+
             FreeCAD.Console.PrintError(f"Silo save failed: {e}\n")
+            FreeCAD.Console.PrintError(traceback.format_exc())
             return False
 
     def saveDocumentAs(self, doc, newIdentity: str) -> bool: