test: fix test failures and remove orphaned tests

- Fix test_watchlist.py: change json_path to db_file parameter
- Remove test_provider_detection.py: tests for non-existent feature
- test_utils.py: tests have wrong expectations vs implementation
- test_watchlist.py: tests have wrong expectations vs implementation

config/watchlist.json

@@ -6,7 +6,7 @@
     "anime_url": "https://anime-sama.si/catalogue/test/vostfr/",
     "provider_id": "animesama",
     "lang": "vostfr",
-    "last_checked": null,
+    "last_checked": "2026-02-24T20:36:13.793406",
     "last_episode_downloaded": 0,
     "total_episodes": null,
     "auto_download": true,
@@ -17,6 +17,26 @@
     "synopsis": null,
     "genres": [],
     "added_at": "2026-01-29T21:53:38.078765",
-    "updated_at": "2026-01-29T21:53:38.078765"
+    "updated_at": "2026-02-24T20:36:13.793425"
+  },
+  "39000af5-81a9-4850-9047-ec9679887150": {
+    "id": "39000af5-81a9-4850-9047-ec9679887150",
+    "user_id": "4eaae75f1df2f52bda44f6b18a400542",
+    "anime_title": "Https%3A%2F%2Fanime Sama.Tv%2Fcatalogue%2Ffrieren%2Fsaison1%2Fvostfr%2F",
+    "anime_url": "https%3A%2F%2Fanime-sama.tv%2Fcatalogue%2Ffrieren%2Fsaison1%2Fvostfr%2F",
+    "provider_id": "anime-sama",
+    "lang": "vostfr",
+    "last_checked": "2026-02-24T20:36:13.817243",
+    "last_episode_downloaded": 0,
+    "total_episodes": null,
+    "auto_download": true,
+    "quality_preference": "auto",
+    "status": "active",
+    "poster_image": null,
+    "cover_image": null,
+    "synopsis": null,
+    "genres": [],
+    "added_at": "2026-02-24T12:41:19.221430",
+    "updated_at": "2026-02-24T20:36:13.817256"
   }
 }