Feature Request: add addressing/visiblity to locally created comments

### What

Having more control for locally made comments.

1. Whether a comment should get federated at all
2. Set audience (addressing)

### Why

The "Polls For ActivityPub" plugin, allows local WordPress users to vote even if for example only the Blog-Actor is active. But then all votes which are stored as a custom comment_type get federated.

Meanwhile I use a hack to set comment_meta->protocol to 'activitypub', but this is no clean solution.

Also I cannot just press "Reply in the Fediverse" and select something like "mentioned users only".

### How

Provide a filters/hooks.

No files or tests are named. Start by locating the code paths for locally created comments, the comment_meta protocol handling, and the “Reply in the Fediverse” flow. Done means providing documented filters or hooks that control whether comments federate and let callers set their audience.

Written by the indexing model from the issue text.