Render: integrated workspace, preview image jobs and opaque PBR (#1046)

Lands the Render workspace (R3), bounded preview-image jobs with cancellation and atomic PNG export (R4a), and opaque PBR looks as one change.

- Render workspace: an overlay-free product preview on the installed GPU device. Returning to Design restores its camera. render.scene and render.settings.apply are added.
- Image jobs: render.preflight/start/status/cancel/export run bounded CPU preview jobs. Export captures the job, overwrite choice and document, and checks the caller's file scope before writing.
- Opaque PBR: looks can carry metal fraction, roughness and dielectric IOR. The product viewport and preview PNG use them; geometry and mass are unchanged. The v1 catalog export refuses PBR rather than dropping it.
- Render setups and PBR looks are saved under design format 21. Labels are in en/de/ja/ko/zh/ru.

Supersedes #706 and #800. Refs #620, #673, #756, #1004.

Contributed by @0xlillith.

Co-authored-by: lillith <35337584+0xlillith@users.noreply.github.com>

crates/doc/src/appearance.rs

@@ -12,11 +12,34 @@ use crate::Document;
 
 /// A look: a name (a library entry's, or "Custom"), sRGB colour and opacity (1 = opaque).
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(try_from = "LookWire")]
 pub struct Look {
     pub name: String,
     pub color: [u8; 3],
     #[serde(default = "opaque")]
     pub opacity: f64,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub pbr: Option<crate::pbr_appearance::PbrParameters>,
+}
+
+#[derive(Deserialize)]
+struct LookWire {
+    name: String,
+    color: [u8; 3],
+    #[serde(default = "opaque")]
+    opacity: f64,
+    #[serde(default)]
+    pbr: Option<crate::pbr_appearance::PbrParameters>,
+}
+
+impl TryFrom<LookWire> for Look {
+    type Error = String;
+    fn try_from(value: LookWire) -> std::result::Result<Self, Self::Error> {
+        if value.pbr.is_some() && value.opacity != 1.0 {
+            return Err("opaque PBR requires opacity 1; refraction/transmission is not supported".into());
+        }
+        Ok(Self { name: value.name, color: value.color, opacity: value.opacity, pbr: value.pbr })
+    }
 }
 
 fn opaque() -> f64 {
@@ -25,7 +48,13 @@ fn opaque() -> f64 {
 
 impl Look {
     pub fn custom(color: [u8; 3], opacity: f64) -> Look {
-        Look { name: "Custom".into(), color, opacity: opacity.clamp(0.0, 1.0) }
+        Look { name: "Custom".into(), color, opacity: opacity.clamp(0.0, 1.0), pbr: None }
+    }
+    pub fn opaque_surface(&self) -> crate::Result<Option<solidcraft_render::surface::OpaqueSurface>> {
+        if self.pbr.is_some() && self.opacity != 1.0 {
+            return Err(crate::DocError::Invalid("opaque PBR requires opacity 1".into()));
+        }
+        self.pbr.map(|p| p.surface(self.color).map_err(|e| crate::DocError::Invalid(e.to_string()))).transpose()
     }
     /// Colour as 0–1 fractions.
     pub fn rgb(&self) -> [f32; 3] {
@@ -109,14 +138,19 @@ pub use defaults::LIBRARY;
 
 /// A library appearance by name (case-insensitive).
 pub fn library(name: &str) -> Option<Look> {
-    LIBRARY.iter().find(|(n, _, _)| n.eq_ignore_ascii_case(name.trim())).map(|(n, c, o)| Look { name: n.to_string(), color: *c, opacity: *o })
+    LIBRARY.iter().find(|(n, _, _)| n.eq_ignore_ascii_case(name.trim())).map(|(n, c, o)| Look {
+        name: n.to_string(),
+        color: *c,
+        opacity: *o,
+        pbr: None,
+    })
 }
 
 /// The look a physical material gives a body that has no appearance of its own.
 pub fn material_look(material: &str) -> Option<Look> {
     let color = crate::material_color(material)?;
     let opacity = if material == "Glass" { 0.25 } else { 1.0 };
-    Some(Look { name: material.to_string(), color, opacity })
+    Some(Look { name: material.to_string(), color, opacity, pbr: None })
 }
 
 impl Document {