[FEATURE]: clarify ctrl+c vs /exit behavior in the TUI docs #23478

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Please clarify the difference between ctrl+c, /exit, and Esc in the TUI docs.

Right now the docs show that ctrl+c is part of app_exit and Esc is session_interrupt, but they do not explain the practical difference between exiting OpenCode and interrupting the current in-progress work.

In practice this is confusing because reconnecting after ctrl+c can still show the current session running, while /exit ends that session instead. A short note in tui.mdx and keybinds.mdx would make this behavior much clearer.