ui: watched-episode state (dimmed + check, next-up highlight), favicon

tests/run.py

@@ -78,6 +78,7 @@ def main():
             asyncio.run(test_browser.test_stream_failure_retry())
             asyncio.run(test_browser.test_recent_searches())
             asyncio.run(test_browser.test_auto_next_countdown())
+            asyncio.run(test_browser.test_episode_watch_state())
 
         print("ALL TESTS PASSED")
     finally: