Refactor model scene definitions (#24508)

* Refactor model scene definitions

* Cleanup

* Validate model paths in the UI

* Handle form validation

frigate/app.py

@@ -49,7 +49,6 @@ from frigate.debug_replay import (
     DebugReplayManager,
     cleanup_replay_cameras,
 )
-from frigate.detectors.detector_config import SceneEnum
 from frigate.detectors.detector_types import api_types
 from frigate.detectors.device import build_detector_config, runner_names
 from frigate.embeddings import EmbeddingProcess, EmbeddingsContext
@@ -108,7 +107,7 @@ class FrigateApp:
         self.metrics_manager = manager
         self.audio_process: mp.Process | None = None
         self.stop_event = stop_event
-        self.detection_queues: dict[SceneEnum, Queue] = {
+        self.detection_queues: dict[str, Queue] = {
             model.scene: mp.Queue() for model in config.models
         }
         self.detectors: dict[str, ObjectDetectProcess] = {}
@@ -395,7 +394,7 @@ class FrigateApp:
                 logger.error("Unable to prepare the %s runtime: %s", detector_type, err)
 
     def start_detectors(self) -> None:
-        model_cameras: dict[SceneEnum, list[str]] = {
+        model_cameras: dict[str, list[str]] = {
             model.scene: [] for model in self.config.models
         }