add refresh topic for camera maintainer recycle action

The maintainer's recycle branch is doing an action (recycle the camera)
in response to a section-level signal. Introduce a
CameraConfigUpdateEnum.refresh case as an explicit action signal — the
maintainer subscribes to refresh instead of detect, parallel with add
and remove. Publishers fire refresh alongside detect when a recycle is
needed; section-level subscribers keep their existing topic.

Since no main-process subscriber listens for detect anymore, the
refresh handler calls recreate_ffmpeg_cmds() explicitly so the shared
CameraConfig's ffmpeg_cmds is rebuilt before the new subprocesses
spawn.

frigate/api/app.py

@@ -751,7 +751,9 @@ def _config_set_in_memory(request: Request, body: AppConfigSetBody) -> JSONRespo
                 )
 
                 # detect resize also republishes motion + objects so other
-                # processes pick up the rebuilt masks
+                # processes pick up the rebuilt masks, and fires refresh so
+                # the camera maintainer recycles the camera process to pick
+                # up the new ffmpeg cmd / SHM sizing
                 if field == "detect":
                     cam_cfg = config.cameras.get(camera)
                     if cam_cfg is not None:
@@ -768,6 +770,12 @@ def _config_set_in_memory(request: Request, body: AppConfigSetBody) -> JSONRespo
                             ),
                             cam_cfg.objects,
                         )
+                        request.app.config_publisher.publish_update(
+                            CameraConfigUpdateTopic(
+                                CameraConfigUpdateEnum.refresh, camera
+                            ),
+                            cam_cfg,
+                        )
 
         return JSONResponse(
             content={"success": True, "message": "Config applied in-memory"},

frigate/camera/maintainer.py

@@ -51,7 +51,7 @@ class CameraMaintainer(threading.Thread):
             [
                 CameraConfigUpdateEnum.add,
                 CameraConfigUpdateEnum.remove,
-                CameraConfigUpdateEnum.detect,
+                CameraConfigUpdateEnum.refresh,
             ],
         )
         self.shm_count = self.__calculate_shm_frame_count()
@@ -281,7 +281,7 @@ class CameraMaintainer(threading.Thread):
                         self.region_grids.pop(camera, None)
                         self.camera_metrics.pop(camera, None)
                         self.ptz_metrics.pop(camera, None)
-                elif update_type == CameraConfigUpdateEnum.detect.name:
+                elif update_type == CameraConfigUpdateEnum.refresh.name:
                     # Recycle replay cameras so detect width/height/fps
                     # propagate through ffmpeg args, SHM sizing, and the
                     # region grid. Regular cameras detect change still
@@ -301,6 +301,10 @@ class CameraMaintainer(threading.Thread):
                         ):
                             continue
 
+                        # rebuild ffmpeg cmds on the shared config so the
+                        # new subprocesses spawn with current args
+                        new_config.recreate_ffmpeg_cmds()
+
                         self.__stop_camera_capture_process(camera)
                         self.__stop_camera_process(camera)
                         self.__unlink_camera_frame_slots(camera)

frigate/config/camera/updater.py

@@ -26,6 +26,7 @@ class CameraConfigUpdateEnum(str, Enum):
     object_genai = "object_genai"
     onvif = "onvif"
     record = "record"
+    refresh = "refresh"  # signals the camera maintainer to recycle the camera process
     remove = "remove"  # for removing a camera
     review = "review"
     review_genai = "review_genai"
@@ -108,7 +109,6 @@ class CameraConfigUpdateSubscriber:
             config.birdseye = updated_config
         elif update_type == CameraConfigUpdateEnum.detect:
             config.detect = updated_config
-            config.recreate_ffmpeg_cmds()
         elif update_type == CameraConfigUpdateEnum.enabled:
             config.enabled = updated_config
         elif update_type == CameraConfigUpdateEnum.object_genai: