Add markers / chapters to the final video if the format allows it

Nobody has claimed this yet.

## Description of proposed feature

OBS (the streaming software) recently added support for adding markers (they call it "chapters") which will produce a marker recognized by Premiere / Resolve etc when imported there. This allows to easily and very precisely find specific point in the video easily since the clip already has it all marked.

This is only supported in a specific format which [OBS calls "hybrid MP4"](https://obsproject.com/kb/hybrid-mp4). Manim could do the same, for example convert sections into these markers in the final output.

## How can the new feature be used?

Since markers are recognized by the video editing software, importing Manim clips into Premiere / Resolve would mean you can attach additional elements (say, audio effects, custom text overlays, etc) directly to specific portions of the Manim clip and it snaps in place due to preexisting markers.

No implementation files or tests are named. Start by reading the linked OBS hybrid MP4 specification and tracing Manim's final video output path; determine how sections are represented and which output formats can carry markers. Done means supported final videos expose section markers in Premiere or Resolve without changing unsupported formats.

Written by the indexing model from the issue text.