Previously, effect callback function types (WritePtyFn, BellFn, TitleChangedFn, etc.) did not receive the terminal that triggered them. This forced callers using the functional option pattern to pre-declare a var and use a split assignment so closures could capture it, as seen in the effects example. All effect callback types now take *Terminal as their first parameter. The C trampolines already recovered the *Terminal from userdata, so they now simply forward it to the Go handler. This lets callers define callbacks inline in NewTerminal without any pre-declaration workaround.