feat(gui): câblage upload diagnostics en fin de run (E3)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/unit/test_gui_v6_diagnostics.py

@@ -108,3 +108,29 @@ def test_flush_spool_sends_and_clears(tmp_path):
     sent = diagnostics.flush_spool(spool, diagnostics.DiagnosticsClient(
         "https://app.aivanov.eu", session=_FakeSession(status_code=200)))
     assert sent == 2 and not spool.exists()
+
+
+def test_tab_send_diagnostics_calls_reporter():
+    import threading
+    from gui_v6.tabs.tab_usage import UsageTab
+
+    tab = object.__new__(UsageTab)  # pas de Tk : on teste juste le helper
+    seen = {}
+    done = threading.Event()
+
+    def reporter(summary):
+        seen["summary"] = summary
+        done.set()
+
+    tab._diag_reporter = reporter
+    tab._send_diagnostics(SimpleNamespace(documents=[], failed=0))
+    assert done.wait(timeout=2.0)
+    assert seen["summary"] is not None
+
+
+def test_tab_send_diagnostics_noop_without_reporter():
+    from gui_v6.tabs.tab_usage import UsageTab
+
+    tab = object.__new__(UsageTab)
+    tab._diag_reporter = None
+    tab._send_diagnostics(SimpleNamespace(documents=[]))  # ne lève pas