Results display (M4) and offscreen full-UI capture (#28)

* ui.capture: the whole window drawn offscreen and rasterised on the CPU

ui.screenshot falls back to it when no frame is presented (hidden window,
locked screen), so agents can look at panels and the toolbar.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Draw the open design and imported surfaces in the viewport

DisplayMesh keeps node labels on every element primitive (for results),
gains add_surface (geometry faces and their boundaries, coincident points
welded) and displaced (elements moved by nodal offsets). Bodies are
tessellated at a thousandth of their size; meshed models show the geometry
as boundaries only.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* results.* commands: deformed shape, contours, mode shapes, animation, reaction sums

The results display is session state (ResultsView), set by commands that are
not edits. Nodal fields (displacement, von Mises, principal and component
stresses; principal stresses in closed form after Smith 1961) and reaction
force and moment sums per set. Results kept from an earlier revision stay
viewable, marked stale; solve.probe says when a result is stale. The Results
tab's display and reaction entries are ready.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Results display: deformed shape, contours with legend, mode shapes and animation, probe, reaction sums

The viewport draws the session's results view: elements moved by their nodes'
displacements or a mode shape (automatic or given scale), faces split exactly
along contour band boundaries into flat-coloured pieces (same on GPU and CPU),
a legend with levels and extremes, a results panel whose controls run the
results.* commands, a click probing the nearest node (solve.probe), and stale
results marked. Solving from the form shows the result on the Results tab.
sample::cantilever is a solvable model for tests and demos.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Simplify the results display (review)

One Contour in the plot; the results scene reuses scene::build; a solve shows
its result through the engine (ResultsView::for_result) and the UI raises the
Results tab when a view appears; the plot's scale and contour values are kept
across animation frames; design bodies are tessellated once per design; the
first content is framed where the display is rebuilt; field_values in one
match; probe reuses results::displacements.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Results display for explicit steps: field frames, energy histories

The results view works on the engine's step results (static, frequency,
explicit): ResultsView.frame and results.frame {frame | time} pick an explicit
field frame; the deformed shape (true scale) and contours (element stresses
averaged to the nodes, velocity) follow it; animation runs through the frames.
The Results panel has a frame slider and plots the kinetic, internal, hourglass
and external energies with their values at the frame. sample::impact is a
steel bar flying onto a rigid wall.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* docs/features.md after the rebase

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

---------

Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture.md

@@ -23,14 +23,14 @@ crates in strictly lower layers.
 | L1 | `modelcraft-mesh` | Surface preparation (weld, watertightness, feature edges), robust predicates, Delaunay tetrahedralization and refinement, Voronoi-based optimization, hex meshing, quality metrics. | started |
 | L1 | `modelcraft-fem` | Element kernels shared by every structural solver: the element table (tet4, tet10, wedge6, hex8 full and incompatible modes, hex20 full and reduced), shape functions, quadrature, element stiffness, consistent and lumped mass, body and pressure loads, stresses and their extrapolation, isotropic and orthotropic elasticity, and the uniform-strain (one-point) hex8 and tet4 kinematics, hourglass shape vectors and element frequency bounds of the explicit solver. Pure functions, no solver loop. | started |
 | L1 | `modelcraft-decks` | Abaqus input, Nastran bulk data and LS-DYNA keyword readers and writers, to and from `model`. Text out, no file system; `deck.write` saves it. | started |
-| L1 | `modelcraft-render` | Display data without a GPU dependency: the visible faces, element edges and nodes of a model, the orbit camera, a CPU rasterizer for headless snapshots; contour maps later. | started |
+| L1 | `modelcraft-render` | Display data without a GPU dependency: the visible faces, element edges and nodes of a model, the orbit camera, a CPU rasterizer for headless snapshots, geometry surfaces with their face boundaries, deformed shapes and banded contour plots of nodal results, picking. | started |
 | L2 | `modelcraft-solver` | Implicit solver: assembly from the resolved model, boundary conditions, sparse direct solution, linear static and modal analysis, stresses and reactions. The lattice Boltzmann solver (`modelcraft-lbm`) joins this layer. | started |
 | L2 | `modelcraft-explicit` | Explicit dynamics: central-difference time integration with lumped mass, one-point hex8 with hourglass control, nodal-pressure tet4, bulk viscosity, rigid walls, energy account, histories and field frames. | started |
 | L3 | `modelcraft-fsi` | Fluid–structure coupling between the L2 solvers (later). | planned |
 | L4 | `modelcraft-doc` | The document: geometry, mesh, model, results, history. | planned |
 | L5 | `modelcraft-io` | `.modelcraft` files (docs/formats/modelcraft.md): text model definition, binary mesh, geometry references with content hashes, the journal; atomic saves; autosave storage for crash recovery. Bytes in, bytes out; the file system only in `fs` and `recovery`. Result files later. | started |
 | L6 | `modelcraft-engine` | Commands (`CommandSpec`), `Session::execute` with rollback and the panic guard, scripts. | started |
-| L7 | `modelcraft-ui-egui`, `modelcraft-mcp` | Desktop UI (egui + wgpu viewport, model tree, commands, status bar) and control channel requests (docs/control-protocol.md); MCP server. | ui started |
+| L7 | `modelcraft-ui-egui`, `modelcraft-mcp` | Desktop UI (egui + wgpu viewport, model tree, commands, status bar, results display with legend, panel and probe, offscreen capture of the whole window) and control channel requests (docs/control-protocol.md); MCP server. | ui started |
 | testkit | `modelcraft-testkit` | Test tooling, a dev-dependency only: the meshing test corpus (`tests/corpus/*/recipe.json`, analytic shapes) and its runner (`cargo xtask corpus`). | started |
 | apps | `modelcraft`, `modelcraft-cli`, `modelcraft-web` | Desktop, command line, browser. | desktop, cli started |