feat(3-2): add recovery tests and story file for automatic recovery on fresh decode

Two-cycle stale→recovery tests confirm that a non-empty fetch after timeout or
empty-list correctly resets is_stale=False; no changes to main.py or aircraft.py
required as recovery logic was already correct from story 3-1.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_stale.py

@@ -69,3 +69,35 @@ def test_stale_cycle_completes_without_crash(renderer: Renderer) -> None:
     # Should complete without any exception
     result = _run_one_cycle(renderer, mock_fetcher, display, last)
     assert isinstance(result, list)
+
+
+def test_recovery_after_timeout_returns_fresh(renderer: Renderer) -> None:
+    display = NullDisplay()
+    last = [_make_aircraft()]
+    mock_fetcher = MagicMock()
+    # Cycle 1: timeout → stale
+    mock_fetcher.fetch.side_effect = requests.Timeout
+    stale_result = _run_one_cycle(renderer, mock_fetcher, display, last)
+    assert stale_result[0].is_stale is True
+    # Cycle 2: fresh fetch → recovery
+    fresh_aircraft = [_make_aircraft(icao="DEF456")]
+    mock_fetcher.fetch.side_effect = None
+    mock_fetcher.fetch.return_value = fresh_aircraft
+    recovered = _run_one_cycle(renderer, mock_fetcher, display, stale_result)
+    assert len(recovered) == 1
+    assert recovered[0].is_stale is False
+    assert recovered[0].icao == "DEF456"
+
+
+def test_recovery_after_empty_returns_fresh(renderer: Renderer) -> None:
+    display = NullDisplay()
+    last = [_make_aircraft()]
+    mock_fetcher = MagicMock()
+    # Cycle 1: empty → stale
+    mock_fetcher.fetch.return_value = []
+    stale_result = _run_one_cycle(renderer, mock_fetcher, display, last)
+    assert stale_result[0].is_stale is True
+    # Cycle 2: non-empty → recovery
+    mock_fetcher.fetch.return_value = [_make_aircraft(icao="GHI789")]
+    recovered = _run_one_cycle(renderer, mock_fetcher, display, stale_result)
+    assert recovered[0].is_stale is False