report: grow the Prompter port and move display_path out of the ui module

Prompter gains interactive(), select() and text() (with the Validator
type), and confirm() now propagates cancellation as Err so flows abort
instead of silently taking a default when the user hits Ctrl+C. The
terminal prompter implements the full port; the port also re-exports
the path display helper, which is pure presentation formatting used by
events and messages rather than terminal code.

src/new/mod.rs

@@ -251,7 +251,7 @@ fn print_success(opts: &NewOptions, outcome: &ScaffoldOutcome) {
     // `display_path` yields an empty string when the target is the cwd
     // itself (Here mode): `Created .` would be cryptic, so spell the
     // location out; the skeleton/path modes keep the `<dir>` display.
-    let display = crate::ui::display_path(&target);
+    let display = crate::report::display_path(&target);
     let location = if display.is_empty() {
         "package in the current directory".to_string()
     } else {