Issue description

Is it possible to trigger a hook/action when a OSC 8 link is clicked? It would be great to click on a OSC 8 file:// or https:// link which triggers a hook with something like HOOK_LINK set to the underlying link. A user can take whatever action they wish to, like open a split pane to show contents of a local file or browse the web... Though I guess tmux will have to provide a setting to not pass the OSC 8 link to the terminal emulator (or both will take action on a link). Terminal emulators do provide a capability to handle OSC 8 sequence clicks, but that's of no use to tmux users who do not want to leave tmux to read a file://, etc.

Additionally, for those who do not use mouse, it will be great to have a key-binding to highlight and navigate between OSC 8 links (perhaps in copy mode) and another key-binding to trigger the same hook or execute a command for currently highlighted link. Thanks!