Miscellaneous improvements (#22714)

* scrub genai API keys and onvif credentials from config endpoint

* enforce camera access in thumbnail tracked-object fallback

The /events/{id}/thumbnail endpoint called require_camera_access when
loading persisted events but skipped the check in the tracked-object
fallback path for in-progress events. A restricted viewer could
retrieve thumbnails from cameras they should not have access to.

* block filter and attach flags in custom ffmpeg export args

The ffmpeg argument blocklist missed -filter_complex, -lavfi, -vf,
-af, -filter, and -attach. These flags can read arbitrary files via
source filters like movie= and amovie=, bypassing the existing -i
block. A user with camera access could exploit this through the
custom export endpoint.

* enforce camera access on VLM monitor endpoint

POST /vlm/monitor allowed any authenticated user to start VLM
monitoring on any camera without checking camera access. A viewer
restricted to specific cameras could monitor cameras they should
not have access to.

* enforce camera access in chat start_camera_watch tool

The start_camera_watch tool called via POST /chat/completion did not
validate camera access, allowing a restricted viewer to start VLM
monitoring on cameras outside their allowed set through the chat
interface.

* restrict review summary endpoint to admin role

* fix require_role call passing string instead of list

* fix section config uiSchema merge replacing base entries

mergeSectionConfig was replacing the entire base uiSchema when a
level override (global/camera) also defined one, causing base-level
ui:after/ui:before directives to be silently dropped. This broke
the SemanticSearchReindex button which was defined in base uiSchema.

frigate/api/media.py

@@ -896,6 +896,7 @@ async def event_thumbnail(
                 if event_id in camera_state.tracked_objects:
                     tracked_obj = camera_state.tracked_objects.get(event_id)
                     if tracked_obj is not None:
+                        await require_camera_access(camera_state.name, request=request)
                         thumbnail_bytes = tracked_obj.get_thumbnail(extension.value)
         except Exception:
             return JSONResponse(
@@ -1066,7 +1067,7 @@ def grid_snapshot(
 
 
 @router.delete(
-    "/{camera_name}/region_grid", dependencies=[Depends(require_role("admin"))]
+    "/{camera_name}/region_grid", dependencies=[Depends(require_role(["admin"]))]
 )
 def clear_region_grid(request: Request, camera_name: str):
     """Clear the region grid for a camera."""