Craft-family shell, native file dialogs, samples and one-click Solve (#46)

* Native file pickers, background opening, drag and drop and recent files

Open (models, SolidCraft designs and tagged meshes in one picker), Save, Save As, Write
Deck and Recover go through the host's file pickers (rfd in the desktop app, injected as
Services so the UI crate stays portable and tests answer them). Files open on a copy of the
session in a worker thread and replace it only on success; files dropped on the window or
named on the command line open the same way. A recent-files list, an unsaved-changes prompt,
Cmd/Ctrl+O/S/Shift+S. Programmatic calls never open a picker: ui.start opens the form.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Samples and one-click Solve: results reachable from the window

file.sample {name} opens a ready-to-run sample (the two parts, the cantilever with static and
frequency steps, the bar impact) in place of the model; solve.run solves every step in order.
Help > Samples, the empty viewport's start screen and the Tools > Samples entry open them
(asking first over unsaved changes); Solve runs in the background like a file opening and the
Results tab comes up. --sample [parts|cantilever|impact] on the command line.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* The Craft-family shell: title bar, workspace ribbon, browser, context panel, timeline

The window now follows SolidCraft's and VectorCraft's layout and themes:
- title bar with the mark, quick actions (File menu, save, undo, redo, Solve, search,
  theme, help), the model's document tab and the version; integrated under the macOS
  traffic lights, own caption buttons and resize zones elsewhere (titlebar.rs);
- workspaces (Prepare, Model, Analysis, Results) with their tabs, and panels of icon
  buttons whose labelled drop-downs list the whole catalogue, coming-soon entries greyed
  with their milestone; panels collapse, then go into a » menu, when narrow;
- the browser: geometry and mesh with eye toggles, definitions with counts, results;
- no permanent Commands list: command search (S, Cmd/Ctrl+K) and a command line;
- the context panel on the right only with context: the command form, results controls,
  the selected definition's properties with Edit and Delete;
- navigation bar and orientation gizmo in the viewport; the journal timeline at the bottom
  with undo positions;
- SolidCraft's light and dark tokens; craft-ui (IconButton, Tab, WidgetPalette).
Menus and the search are view state (ui.set {menu, palette}), so captures show them.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Shell polish, docs and licences

Menus painted as the family's (flat File menu with recent files, decks and samples), the
legend sized to its text, two-line panel labels inside the ribbon, glyphs the UI font has,
offscreen captures without fade-in, ui.start runs in-window file actions (samples, recover,
solve) but never a native picker, ui.select. Control protocol, architecture, ROADMAP, AGENTS
and ATTRIBUTION updated; THIRD-PARTY-LICENSES.txt with craft-ui and rfd.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Title bar mark from the application icon; fluid steps and domains in the shell

The title bar draws the app icon's bracket (assets/app-icon/icon-small.svg's faces) as
SolidCraft draws its mark; the window keeps its title-bar flags after the rebase.
solve.run solves fluid steps too (solve.fluid); the browser lists fluid domains.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Simplify: cached per-frame data, one command per timeline roll, workspace setters

- Icon textures are kept per pixel size (the shell draws several sizes a frame; the cache
  used to clear on every size change and rasterise again).
- Opening a model or recovering one starts from an empty session instead of copying the
  current one; the replaced session is freed off the window thread.
- Element counts, timeline items, search results and the selected definition's properties
  are cached until what they show changes; timeline tooltips are built on hover; long lists
  in properties are summarised.
- edit.undo and edit.redo take a count: a timeline click is one command.
- solve.run dispatches on the step's procedure (no string round trip) and reports its name.
- The workspace and tab change together through UiState::select_tab/select_workspace
  (ui.set {workspace} alone now sticks); no per-frame syncing.
- One busy guard, Kind::verbs, a fit flag for background jobs, ModelApp::home_view, the title
  bar's actions as an enum, dead code removed.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Title bar: Solve and tools at the right end; no traffic-light inset in full screen

The owner's feedback on the title bar: Solve, search, theme and help sit at its right end
before the version; on macOS the left group (mark, name, quick actions) moves into the
traffic lights' room in full screen, where there are none, and back when leaving it. The
layout is a pure function (bar_layout) tested for both states, narrow windows and custom
caption buttons. ui.fullscreen {on} for agents.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* Caps labels in Inter SemiBold

egui has no bold weight of its default font, so the ribbon's tabs and panel labels, the
workspace switcher and its menu, menu headings, the browser header, the context panel's
headers and the Solve label were thin, especially in the light theme. They now use a label
font family: Inter SemiBold 4.1 (SIL OFL 1.1, unmodified, fonts/OFL.txt, ATTRIBUTION.md),
with egui's fonts as fallback, installed with the theme on the live and offscreen contexts.
theme::label_font falls back to the default font until the family is bound (fonts take
effect from the next pass), so nothing can panic. Panels widen to their label's longest word.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

* docs: regenerate features.md after rebase

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

---------

Co-authored-by: jyviko <[email protected]>
Co-authored-by: Claude Opus 5.5 <[email protected]>

ROADMAP.md

@@ -34,4 +34,4 @@ hex meshes today and it gives the best elements where stresses are read.
 | M13 Fluid–structure interaction | Immersed-boundary coupling of the lattice Boltzmann fluid with the explicit or implicit structure; interface force transfer; sub-cycling; Aitken then interface quasi-Newton coupling; free-surface flow | planned |
 | M14 Blast and impact fluids | EOS-driven fluids in the explicit solver: ALE multi-material or SPH, with fluid–structure contact | planned |
 | Continuous: verification and validation | Every capability checked against theory (closed forms), experiments (published measurements) and published benchmarks (NAFEMS, vendor benchmark and verification manuals such as Abaqus's), each case our own model in `tests/oracle/` with its cited reference and tolerance; `cargo xtask oracle` runs them and writes docs/oracle.md; once a case matches, our result is frozen as a fixture so fidelity cannot regress (docs/verification.md). Runner, fixtures and CI job: done; 26 theory cases (patch tests of every solid element, cantilevers, Lamé in 3D, plane strain and axisymmetric, Kirsch in 3D and plane stress, rotating disc and cylinder, beam frequencies, couplings, explicit waves, impact and J2 plasticity, CDT invariants), 9 published benchmarks (MacNeal–Harder solid tests, Scordelis–Lo with solids, NAFEMS LE1 in 3D and 2D, LE10, FV32) and 9 pending cases with citations (shells, thermal, static plasticity, Taylor bar, CFD); `mesh.block` mapped blocks and 2D patches build their meshes | started |
-| Continuous: desktop and agents | Desktop app (viewport, model tree, commands, control channel, the open design drawn, `ui.capture` of the whole window offscreen: done; toolbar of every capability from the catalogue, ready or coming soon with its milestone, icons drawn with VectorCraft, docs/features.md: done), MCP server, browser build, command schema as the public API | started |
+| Continuous: desktop and agents | Desktop app (viewport, model tree, commands, control channel, the open design drawn, `ui.capture` of the whole window offscreen: done; toolbar of every capability from the catalogue, ready or coming soon with its milestone, icons drawn with VectorCraft, docs/features.md: done; the Craft-family shell — title bar, workspaces and ribbon drop-downs, browser, context panel, command search, journal timeline, light and dark themes — native file pickers with background opening, drag and drop and recent files, samples and one-click Solve: done), MCP server, browser build, command schema as the public API | started |