Fix premature evaluation after blinking completes

When transitioning from STATE_BLINKING to STATE_WAIT_FOR_INPUT, the script used a stale timestamp `now` from before the blocking `blink_led` function. This caused the puzzle to immediately evaluate as failed. Updated to use `time.time()` after blinking finishes to ensure the user gets the full 3 seconds to enter their answer.

tests/test_wecker.py

@@ -103,3 +103,17 @@ def test_state_machine_incorrect(mock_gpio, mock_pygame):
     assert keep_running
     assert clock.state == wecker.STATE_WAIT_BEFORE_RETRY
 
+
+@patch('wecker.time.time')
+def test_blinking_updates_time_correctly(mock_time, mock_gpio, mock_pygame):
+    clock = wecker.AlarmClock()
+    clock.state = wecker.STATE_BLINKING
+    clock.target_blinks = 4
+    
+    mock_time.return_value = 200.0
+    
+    with patch('wecker.blink_led'):
+        clock.update(100.0, False) 
+        
+    assert clock.state == wecker.STATE_WAIT_FOR_INPUT
+    assert clock.last_interaction_time == 200.0