[Proof editor] add "-unsigned" to the default proof filename when app…

…licable

When signing stakes in a different wallet than the wallet controlling the master key, the proof signature will be all 0s. Reflect this in the file name when saving the proof, to help with managing the files during the multi-step signing procedure.

electroncash_gui/qt/avalanche_dialogs.py

@@ -578,10 +578,16 @@ def on_save_proof_clicked(self):
                 "No proof to be saved. The save button should not be enabled."
             )
         proof = Proof.from_hex(self.proof_display.toPlainText())
+
+        default_filename = f"{proof.proofid.get_hex()[:8]}"
+        if not proof.verify_master_signature():
+            default_filename += "-unsigned"
+        default_filename += ".proof"
+
         fileName, __ = QtWidgets.QFileDialog.getSaveFileName(
             self,
             "Save proof to file",
-            f"{proof.proofid.get_hex()[:8]}.proof",
+            default_filename,
             filter="Avalanche proof (*.proof);;All files (*)",
         )
         if not fileName: