engine: show temperature and wall heat in fluid results

Route saved temperature through slices, obstacle surfaces, streamlines and both result views, with availability and model units shared by commands and the UI. Show signed obstacle heat histories per complete face area at the selected frame, leaving unrecorded times uncoloured and retaining the saved slice settings.

Part of #157.

crates/ui-egui/src/results_panel.rs

@@ -41,7 +41,8 @@ pub fn show(app: &mut ModelApp, ui: &mut egui::Ui, rect: Rect, t: &Tokens) {
     probe(app, &plot, &painter, rect, t);
     let mut focus = None;
     for (i, (line, node)) in extremes.into_iter().enumerate() {
-        let r = ui.interact(line, ui.id().with(("fc_legend_extreme", i)), egui::Sense::click()).on_hover_text(format!("Show and probe node {node}"));
+        let tip = if plot.is_fluid() { "Centre this field extreme".into() } else { format!("Show and probe node {node}") };
+        let r = ui.interact(line, ui.id().with(("fc_legend_extreme", i)), egui::Sense::click()).on_hover_text(tip);
         if r.hovered() {
             ui.ctx().set_cursor_icon(egui::CursorIcon::PointingHand);
         }
@@ -86,6 +87,7 @@ fn title(plot: &Plot) -> String {
     match (&plot.contour, plot.mode()) {
         (Some(l), _) => l.field.title(&plot.result, plot.units),
         (None, Some(_)) => "Mode shape (normalised)".into(),
+        (None, None) if plot.is_fluid() => plot.view.contour.map_or_else(|| "Flow".into(), |f| f.title(&plot.result, plot.units)),
         (None, None) => "Deformed shape".into(),
     }
 }
@@ -474,9 +476,23 @@ fn deformation_rows(plot: &Plot, ui: &mut egui::Ui, run: &mut Vec<(&'static str,
 fn flow_rows(plot: &Plot, ui: &mut egui::Ui, run: &mut Vec<(&'static str, Value)>) {
     use fieldcraft_engine::flow::{Axis, slice_position};
     let (Kind::Fluid(f), Some(flow)) = (plot.result.kind(), plot.flow.as_ref()) else { return };
+    if plot.view.contour == Some(Field::WallHeatFlux) {
+        ui.label("Wall heat");
+        ui.label("Positive into wall; face average");
+        ui.end_row();
+        if plot.contour.is_none() {
+            ui.label("History");
+            ui.label("No wall heat recorded at this frame");
+            ui.end_row();
+        }
+    }
     let view = &flow.view;
     ui.label("Slice");
     ui.horizontal(|ui| {
+        if plot.view.contour == Some(Field::WallHeatFlux) {
+            ui.label("Hidden for wall heat");
+            return;
+        }
         let shown = view.slice.as_ref().map_or("None", |s| s.axis.id());
         egui::ComboBox::from_id_salt("fc_results_slice").selected_text(format!("Normal {}", shown.to_uppercase())).width(90.0).show_ui(ui, |ui| {
             if ui.selectable_label(view.slice.is_none(), "None").clicked() {
@@ -504,14 +520,14 @@ fn flow_rows(plot: &Plot, ui: &mut egui::Ui, run: &mut Vec<(&'static str, Value)
     ui.end_row();
     ui.label("Obstacles");
     let mut surface = view.surface;
-    if ui.checkbox(&mut surface, "Coloured").on_hover_text("Colour the part by the field in the fluid beside it").changed() {
+    if ui.checkbox(&mut surface, "Coloured").on_hover_text("Colour the part by the selected fluid field or wall heat").changed() {
         run.push(("results.surface", json!({"show": surface})));
     }
     ui.end_row();
     ui.label("Streamlines");
     ui.horizontal(|ui| {
         let mut on = view.streamlines.is_some();
-        if ui.checkbox(&mut on, "").on_hover_text("Streamlines from the inlet, coloured by speed when the legend shows velocity").changed() {
+        if ui.checkbox(&mut on, "").on_hover_text("Streamlines from the inlet, coloured by speed or temperature when selected").changed() {
             run.push(("results.streamlines", json!({"show": on})));
         }
         if let Some(sl) = &view.streamlines {