Hands: fix Export doing nothing, and show it's busy at once

af2ea7c put _stay_awake between exportSession and its @Slot, so the
window's Export button called a method QML couldn't see. A new test checks
every backend call in main.qml against Backend's slots and properties.
Export and Upload now say Exporting…/Uploading… with a spinner the moment
they're pressed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

hands/rec/ft_handrec.py

@@ -787,7 +787,6 @@ class Backend(QObject):
     def exportSessionId(self):
         return self._export_session
 
-    @Slot(str, bool)
     def _stay_awake(self, why, on):
         """Hold off sleep while an export or upload runs, so the headset can be taken off and
         left plugged in: a host unit running systemd-inhibit, started with the first reason
@@ -812,6 +811,7 @@ class Backend(QObject):
                     print(f"keeping the Frame awake: {e}", file=sys.stderr, flush=True)
         self._thread(run)
 
+    @Slot(str, bool)
     def exportSession(self, session, keep_notes):
         if self.exporting or self._active_guard(session):
             return

hands/rec/main.qml

@@ -1396,12 +1396,20 @@ Kirigami.ApplicationWindow {
                 }
                 RowLayout {
                     Controls.Button {
-                        text: exportView.chosen && exportView.chosen.exported ? "Export again" : "Export"
+                        text: backend.exporting ? "Exporting…"
+                              : exportView.chosen && exportView.chosen.exported ? "Export again" : "Export"
                         icon.name: "document-export"
                         enabled: exportView.chosen !== null && !backend.exporting && backend.zstdFound
                                  && !exportView.chosen.active
                         onClicked: backend.exportSession(exportView.chosen.id, false)
                     }
+                    // Shows the moment Export is pressed: the first progress can take a few seconds.
+                    Controls.BusyIndicator {
+                        visible: backend.exporting
+                        running: visible
+                        implicitWidth: Kirigami.Units.gridUnit * 1.5
+                        implicitHeight: implicitWidth
+                    }
                     Controls.Button {
                         visible: backend.exporting
                         text: "Cancel"
@@ -1426,7 +1434,7 @@ Kirigami.ApplicationWindow {
                 }
                 Controls.Label {
                     Layout.maximumWidth: Kirigami.Units.gridUnit * 26
-                    visible: backend.exportText !== "" && backend.exportSessionId === sessionBox.currentValue
+                    visible: backend.exportText !== "" && (backend.exporting || backend.exportSessionId === sessionBox.currentValue)
                     wrapMode: Text.WrapAnywhere
                     text: backend.exportText
                 }
@@ -1643,11 +1651,17 @@ Kirigami.ApplicationWindow {
                 RowLayout {
                     visible: uploadView.session !== ""
                     Controls.Button {
-                        text: backend.hubDryRun ? "Upload (dry run)" : "Upload"
+                        text: backend.uploading ? "Uploading…" : backend.hubDryRun ? "Upload (dry run)" : "Upload"
                         icon.name: "cloud-upload"
                         enabled: uploadView.blocked === "" && !backend.uploading
                         onClicked: uploadView.startUpload()
                     }
+                    Controls.BusyIndicator {
+                        visible: backend.uploading
+                        running: visible
+                        implicitWidth: Kirigami.Units.gridUnit * 1.5
+                        implicitHeight: implicitWidth
+                    }
                     Controls.Button {
                         visible: backend.uploading
                         text: "Cancel"

hands/rec/tests/test_qml_backend.py

@@ -0,0 +1,43 @@
+#!/usr/bin/env python3
+"""main.qml against ft_handrec.Backend: every backend.name(...) the window calls is a slot, and
+every backend.name it reads is a property or a slot. A method that lost its @Slot shows up in
+QML only as "is not a function" when its button is pressed (2026-10-03: Export did nothing).
+Needs PySide6 (the dev container); skipped without it.
+
+  python3 hands/rec/tests/test_qml_backend.py
+"""
+import os
+import re
+import sys
+import unittest
+
+HERE = os.path.dirname(os.path.abspath(__file__))
+REC = os.path.dirname(HERE)
+sys.path.insert(0, REC)
+
+
+class QmlBackendTest(unittest.TestCase):
+    def setUp(self):
+        try:
+            import ft_handrec
+        except ImportError as e:
+            self.skipTest(f"no PySide6: {e}")
+        meta = ft_handrec.Backend.staticMetaObject
+        self.slots = {bytes(meta.method(i).name()).decode() for i in range(meta.methodCount())}
+        self.props = {meta.property(i).name() for i in range(meta.propertyCount())}
+        with open(os.path.join(REC, "main.qml")) as f:
+            self.qml = f.read()
+
+    def test_calls_are_slots(self):
+        called = set(re.findall(r"\bbackend\.(\w+)\s*\(", self.qml))
+        self.assertTrue(called)
+        self.assertEqual(sorted(called - self.slots), [], "called from main.qml but not a slot")
+
+    def test_reads_exist(self):
+        read = set(re.findall(r"\bbackend\.(\w+)\b(?!\s*\()", self.qml))
+        self.assertTrue(read)
+        self.assertEqual(sorted(read - self.props - self.slots), [], "read in main.qml but not on Backend")
+
+
+if __name__ == "__main__":
+    unittest.main()