report: add BuildView/Prompter ports and drive pkh build through them

Core flows no longer reach into the terminal UI: build_source_package
takes a BuildSourceOptions struct (source tree, domain options, view,
prompter) and reports phases, messages and outcomes through the
environment-agnostic ports in the new report module. The classifiers
move from ui/logfmt to the core logfmt module, DebUi becomes a
BuildView adapter, the re-vendor retry asks the prompter instead of
checking for a TTY, and artifact/success printing moves to the CLI.

Headless consumers pass report::Quiet; an embedding (e.g. a builder
server forwarding events to a web frontend) implements BuildView and
maps the plain-data events onto its own wire format.

src/new/questions.rs

@@ -593,12 +593,13 @@ pub async fn offer_verification(
         return;
     }
 
-    let ui = Some(std::sync::Arc::new(crate::ui::deb::DebUi::new(multi)));
-    if let Err(e) = crate::build::build_source_package(
-        Some(&tree),
-        crate::build::SourceBuildOptions::default(),
-        ui,
-    ) {
+    let ui = std::sync::Arc::new(crate::ui::deb::DebUi::new(multi));
+    if let Err(e) = crate::build::build_source_package(crate::build::BuildSourceOptions {
+        source: Some(tree.clone()),
+        options: crate::build::SourceBuildOptions::default(),
+        view: &*ui,
+        prompter: &crate::ui::prompt::TerminalPrompter,
+    }) {
         log::error!("Verification source build failed: {e}");
         log::info!(
             "The scaffolded tree is intact. Inspect it, then retry with \