dev: umfangreiches Refactoring, Trakt-Integration und Code-Review-Fixes (0.1.69-dev)

Core & Architektur:
- Neues Verzeichnis addon/core/ mit router.py, trakt.py, metadata.py,
  gui.py, playstate.py, plugin_manager.py, updater.py
- Tests-Verzeichnis hinzugefügt (24 Tests, pytest + Coverage)

Trakt-Integration:
- OAuth Device Flow, Scrobbling, Watchlist, History, Calendar
- Upcoming Episodes, Weiterschauen (Continue Watching)
- Watched-Status in Episodenlisten
- _trakt_find_in_plugins() mit 5-Min-Cache

Serienstream-Suche:
- API-Ergebnisse werden immer mit Katalog-Cache ergänzt (serverseitiges 10-Treffer-Limit)
- Katalog-Cache wird beim Addon-Start im Daemon-Thread vorgewärmt
- Notification nach Cache-Load via xbmc.executebuiltin() (thread-sicher)

Bugfixes (Code-Review):
- Race Condition auf _TRAKT_WATCHED_CACHE: _TRAKT_WATCHED_CACHE_LOCK hinzugefügt
- GUI-Dialog aus Daemon-Thread: xbmcgui -> xbmc.executebuiltin()
- ValueError in Trakt-Watchlist-Routen abgesichert
- Token expires_at==0 Check korrigiert
- get_setting_bool() Kontrollfluss in gui.py bereinigt
- topstreamfilm_plugin: try-finally um xbmcvfs.File.close()

Cleanup:
- default.py.bak und refactor_router.py entfernt
- .gitignore: /tests/ Eintrag entfernt
- Type-Hints vereinheitlicht (Dict/List/Tuple -> dict/list/tuple)

tests/test_serienstream_perf.py

@@ -0,0 +1,48 @@
+import os
+import time
+import pytest
+
+from addon.plugins.serienstream_plugin import SerienstreamPlugin
+
+
+@pytest.mark.live
+@pytest.mark.perf
+def test_live_titel_staffel_episode_timing():
+    if not os.getenv("LIVE_TESTS"):
+        pytest.skip("LIVE_TESTS not set")
+
+    title = os.getenv("LIVE_TITLE", "Star Trek: Starfleet Academy")
+    season = os.getenv("LIVE_SEASON", "Staffel 1")
+
+    max_title_to_season = float(os.getenv("PERF_MAX_TITLE_TO_SEASON", "6.0"))
+    max_season_to_episodes = float(os.getenv("PERF_MAX_SEASON_TO_EPISODES", "5.0"))
+
+    plugin = SerienstreamPlugin()
+
+    t0 = time.perf_counter()
+    seasons = plugin.seasons_for(title)
+    t1 = time.perf_counter()
+
+    assert seasons, f"Keine Staffeln für Titel gefunden: {title}"
+    assert season in seasons, f"Gewünschte Staffel fehlt: {season}; vorhanden: {seasons}"
+
+    episodes = plugin.episodes_for(title, season)
+    t2 = time.perf_counter()
+
+    assert episodes, f"Keine Episoden für {title} / {season}"
+
+    title_to_season = t1 - t0
+    season_to_episodes = t2 - t1
+
+    print(
+        f"PERF title->seasons={title_to_season:.3f}s "
+        f"season->episodes={season_to_episodes:.3f}s "
+        f"episodes={len(episodes)}"
+    )
+
+    assert title_to_season <= max_title_to_season, (
+        f"title->seasons zu langsam: {title_to_season:.3f}s > {max_title_to_season:.3f}s"
+    )
+    assert season_to_episodes <= max_season_to_episodes, (
+        f"season->episodes zu langsam: {season_to_episodes:.3f}s > {max_season_to_episodes:.3f}s"
+    )