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.

ROADMAP.md

@@ -123,3 +123,10 @@ What exists and what is missing, by area; each gap is in a milestone above.
 | Fluid dynamics | LBM D3Q19 TRT, walls, inlets/outlets, obstacle forces | Turbulence with wall models, thermal and conjugate heat transfer, non-Newtonian, porous media, multiphase, GPU (M12, M13) |
 | Wave propagation | One-dimensional elastic waves and impact in the explicit solver (bar cases in the oracle) | A 2D/3D finite-difference ultrasound solver (velocity–stress FDTD, EFIT, k-space pseudospectral) on voxelised geometry, time–frequency diagrams (spectrogram, wavelet, Wigner–Ville) with dispersion overlays, spectral elements, absorbing boundaries, tone-burst and transducer sources, attenuation, Lamb/Rayleigh/Love guided waves and SAFE dispersion curves, ultrasound in fluids and tissue, nonlinear acoustics, A/B-scans and frequency–wavenumber analysis (M23) |
 | Design | — | Parametric studies on SolidCraft parameters, optimisation, submodelling (M22) |
+
+### Heated flow results (#157)
+
+Temperature is available on fluid slices, obstacle surfaces and streamline colours when the
+saved frames carry it. Signed face-average wall heat follows recorded histories and the
+model's power/area units. Commands, the Results panel and headless pictures share the view;
+initial frames without recorded wall heat remain uncoloured.