feat(examples): add workout replay e2e

Wrap the workout page with the shared runtime, add export replay over command/event truth, and cover the running HTTP app with an end-to-end test that exercises runtime asset loading and product interactions.

req: examples/001

req: local/001

req: local/003

req: local/004

req: host/001

examples/workout/src/lib.rs

@@ -212,6 +212,38 @@ impl WorkoutState {
             .collect::<Vec<_>>()
             .join("\n")
     }
+
+    pub fn export_event_log(&self) -> String {
+        // req: local/003
+        self.events
+            .iter()
+            .map(WorkoutEvent::to_export_line)
+            .collect::<Vec<_>>()
+            .join("\n")
+    }
+
+    fn replay_export(&mut self, export: &str) -> usize {
+        // req: local/001 req: local/003 req: local/004
+        let events = export
+            .lines()
+            .filter_map(WorkoutEvent::from_export_line)
+            .collect::<Vec<_>>();
+        let mut replayed = WorkoutState::demo();
+        for event in &events {
+            replayed.events.push(event.clone());
+            replayed.project(event);
+        }
+        replayed.host_status = format!(
+            "Replayed {} exported events into a fresh projection; app policy still owns sync.",
+            events.len()
+        );
+        *self = replayed;
+        events.len()
+    }
+}
+
+fn export_field(value: &str) -> String {
+    value.replace(['\t', '\n', '\r'], " ")
 }
 
 impl WorkoutEvent {
@@ -230,6 +262,52 @@ impl WorkoutEvent {
             Self::NoteRecorded { text } => format!("note: {text}"),
         }
     }
+
+    fn to_export_line(&self) -> String {
+        // req: local/003
+        match self {
+            Self::SetCompleted {
+                exercise,
+                set,
+                reps,
+                kg,
+            } => format!(
+                "set_completed\t{}\t{set}\t{reps}\t{kg}",
+                export_field(exercise)
+            ),
+            Self::WeightChanged { exercise, kg } => {
+                format!("weight_changed\t{}\t{kg}", export_field(exercise))
+            }
+            Self::ExerciseSkipped { exercise } => {
+                format!("exercise_skipped\t{}", export_field(exercise))
+            }
+            Self::NoteRecorded { text } => format!("note_recorded\t{}", export_field(text)),
+        }
+    }
+
+    fn from_export_line(line: &str) -> Option<Self> {
+        // req: local/003
+        let fields = line.split('\t').collect::<Vec<_>>();
+        match fields.as_slice() {
+            ["set_completed", exercise, set, reps, kg] => Some(Self::SetCompleted {
+                exercise: (*exercise).into(),
+                set: set.parse().ok()?,
+                reps: reps.parse().ok()?,
+                kg: kg.parse().ok()?,
+            }),
+            ["weight_changed", exercise, kg] => Some(Self::WeightChanged {
+                exercise: (*exercise).into(),
+                kg: kg.parse().ok()?,
+            }),
+            ["exercise_skipped", exercise] => Some(Self::ExerciseSkipped {
+                exercise: (*exercise).into(),
+            }),
+            ["note_recorded", text] => Some(Self::NoteRecorded {
+                text: (*text).into(),
+            }),
+            _ => None,
+        }
+    }
 }
 
 #[derive(Hemplate)]
@@ -237,9 +315,23 @@ pub struct Workout {
     pub next_action: String,
     pub status: String,
     pub event_log: String,
+    pub export_payload: String,
     pub host_status: String,
 }
 
+#[derive(Hemplate)]
+pub struct AppShell {
+    pub runtime_src: &'static str,
+    pub body: Html,
+}
+
+pub fn page(runtime_src: &'static str, state: &WorkoutState) -> Html {
+    ui::render(&AppShell {
+        runtime_src,
+        body: render(state),
+    })
+}
+
 pub fn view(state: &WorkoutState) -> Workout {
     Workout {
         next_action: state.projection.next_action.clone(),
@@ -249,6 +341,7 @@ pub fn view(state: &WorkoutState) -> Workout {
             state.events.len()
         ),
         event_log: state.event_log_text(),
+        export_payload: state.export_event_log(),
         host_status: state.host_status.clone(),
     }
 }
@@ -263,6 +356,7 @@ fn effects(state: &WorkoutState, status: impl Into<String>) -> impl IntoEffect {
         ui::workout::next_action.text(&state.projection.next_action),
         ui::workout::status.text(status.into()),
         ui::workout::event_log.text(state.event_log_text()),
+        ui::workout::export_payload.text(state.export_event_log()),
         ui::workout::host_status.text(&state.host_status),
     )
 }
@@ -307,6 +401,15 @@ pub fn record_note(app: &AppState, text: impl Into<String>) -> impl IntoEffect {
     })
 }
 
+pub fn replay_export(app: &AppState) -> impl IntoEffect {
+    app.update(|state| {
+        // req: local/001 req: local/003 req: local/004
+        let export = state.export_event_log();
+        let count = state.replay_export(&export);
+        effects(state, format!("Replayed {count} exported workout events"))
+    })
+}
+
 pub fn export_log(app: &AppState) -> impl IntoEffect {
     app.update(|state| {
         // req: host/001 req: host/004 req: local/003
@@ -441,6 +544,33 @@ mod tests {
         );
     }
 
+    #[test]
+    fn export_payload_replays_into_projection_before_ui_effects() {
+        // req: local/001 req: local/003 req: local/004
+        let app = AppState::demo();
+        run(|()| complete_set(&app), ());
+        run(|()| change_weight(&app, 28.0), ());
+        let export = app.with_workout(WorkoutState::export_event_log);
+        assert!(export.contains("set_completed\tGoblet squat\t1\t8\t24"));
+        assert!(export.contains("weight_changed\tGoblet squat\t28"));
+
+        let replay = run(|()| replay_export(&app), ());
+        assert!(contains_payload_text(
+            &replay,
+            "Replayed 2 exported workout events"
+        ));
+        assert_eq!(
+            app.with_workout(|state| {
+                (
+                    state.events.len(),
+                    state.projection.completed_sets_for_current,
+                    state.plan[0].kg,
+                )
+            }),
+            (2, 1, 28.0)
+        );
+    }
+
     #[test]
     fn host_export_result_returns_through_app_code() {
         // req: host/001 req: host/002 req: host/005 req: local/003