Miscellaneous fixes (0.18 beta) (#23934)

* add host npu requirements to docs

* allow toggling live audio transcription via mqtt

* improve spacing consistency on mobile drawers

* fix clearing the region grid not surviving a restart

frigate/api/media.py

@@ -53,6 +53,7 @@ from frigate.util.file import (
 )
 from frigate.util.image import get_image_from_recording, get_image_quality_params
 from frigate.util.media import get_keyframe_before
+from frigate.util.object import create_empty_regions_grid
 
 logger = logging.getLogger(__name__)
 
@@ -1083,7 +1084,21 @@ def clear_region_grid(request: Request, camera_name: str):
             status_code=404,
         )
 
-    Regions.delete().where(Regions.camera == camera_name).execute()
+    # store an empty grid instead of deleting the row so the grid is
+    # rebuilt from newly tracked objects and not from all past history
+    region = {
+        Regions.camera: camera_name,
+        Regions.grid: create_empty_regions_grid(),
+        Regions.last_update: datetime.now().timestamp(),
+    }
+    (
+        Regions.insert(region)
+        .on_conflict(
+            conflict_target=[Regions.camera],
+            update=region,
+        )
+        .execute()
+    )
     return JSONResponse(
         content={"success": True, "message": "Region grid cleared"},
     )