Merge remote-tracking branch 'origin/master' into dev

Resolve conflicts in the export pipeline where dev's job-queue refactor
met master's chapter-metadata and security work.

- Unify chapter support under ChaptersEnum (none / recording_segments /
  review_items); the realtime stream-copy export selects the per-segment
  or per-review-item builder by the camera's configured mode. Thread
  chapters through ExportRecordingsBody -> _build_export_job -> ExportJob
  -> RecordingExporter.
- Keep master's creation_time/comment export metadata and fix a
  video_path duplication the textual merge introduced in the preview
  command.
- Move the chapters request field to ExportRecordingsBody (the single
  export endpoint) where it is actually honored.

Restore security fixes the automatic merge would have reverted:
- frigate/util/services.py: restore the #23493 rename to the public
  is_go2rtc_arbitrary_exec_allowed so create_config.py's dynamic-source
  exec guard imports and runs (the merge otherwise left a broken import).
- Preserve the export image-path ".." traversal check inside
  _sanitize_existing_image, applied to single/custom/batch exports.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frigate/api/camera.py

@@ -147,6 +147,19 @@ def go2rtc_camera_stream(request: Request, stream_name: str):
 )
 def go2rtc_add_stream(request: Request, stream_name: str, src: str = ""):
     """Add or update a go2rtc stream configuration."""
+    if src and is_restricted_go2rtc_source(src):
+        logger.warning(
+            "Rejected go2rtc stream '%s' with restricted source type (echo/expr/exec)",
+            stream_name,
+        )
+        return JSONResponse(
+            content={
+                "success": False,
+                "message": "Restricted stream source type",
+            },
+            status_code=400,
+        )
+
     try:
         params = {"name": stream_name}
         if src: