Render preview uses the shared camera navigation (#1462)

* Render preview uses the shared camera navigation

The Render workspace's product preview had its own hard-coded camera
controls. Camera input now lives in one component, navigation::handle,
which the modelling viewport and the Render preview both call (NavCaps:
orbit, pick). Render gets the navigation preset, Orbit around, zoom to the
cursor, the middle double-click and the axis view or navigation cube.
Flat pages can call it with orbit off. A test rejects pages that read the
wheel or move the camera themselves.

Fixes #1454

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Render panel hint says the camera moves as in Design

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

AGENTS.md

@@ -81,6 +81,10 @@ People trust SolidCraft with their designs; a crash loses their work. **This out
   egui/eframe/winit/wgpu/rfd. **The UI crate is swappable.** Only `crates/kernel` may use `truck`.
 - **The UI is thin**: panels read engine state and act through `app.run(id, params)` /
   `app.start(id)`. Colours come from `theme::Tokens`.
+- **One set of camera controls**: every page or canvas with a camera (viewport, Render
+  preview, future flat pattern or drawing pages) calls `navigation::handle` with its `NavCaps`
+  (orbit off for flat 2D pages). New canvases must use `navigation::handle`; never hand-roll
+  camera input (a test rejects it).
 - **Rust only.** Units are millimetres and radians internally; Z is up. The one exception is
   JavaScript the browser requires: the service worker `apps/solidcraft-web/sw.js` (browsers only
   run service workers as JavaScript) and the small inline scripts in `apps/solidcraft-web/index.html`.