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/put/mod.rs

@@ -521,7 +521,7 @@ fn discover_changes(cwd: &Path) -> Result<PathBuf, Box<dyn std::error::Error>> {
              Pass the one to upload explicitly",
             entry.source,
             many.iter()
-                .map(|p| ui::display_path(p))
+                .map(|p| crate::report::display_path(p))
                 .collect::<Vec<_>>()
                 .join(", ")
         )