build(web): restore the wasm build — gate native-only deps off wasm

The web build had bit-rotted: native-only features added since it last
compiled pulled crates that don't build for wasm32-unknown-unknown.

- printpdf (PDF export / printing) → native-only target; the web build gets
  stub export_pdf / print_wires. It pulls a wasm-incompatible memchr 1.0.2
  via lopdf → nom_locate, and the web has no filesystem.
- getrandom 0.3 (via ahash via acadrust) → enable its wasm_js feature and add
  the matching --cfg getrandom_backend rustflag in .cargo/config.toml.
- ocs_plugin_api "host" feature (out-of-process plugin runtime: interprocess,
  libloading, memmap2, rkyv) → native-only target; the web gets the
  dependency-free manifest/ribbon contract. The host code was already
  wasm-gated; only the Cargo wiring pulled it in unconditionally.

`trunk build --release` succeeds again.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.cargo/config.toml

@@ -0,0 +1,6 @@
+# getrandom 0.3 (pulled by ahash via acadrust) needs this cfg to select its
+# browser backend on wasm32-unknown-unknown, alongside its `wasm_js` feature
+# (enabled in Cargo.toml for the wasm target). Without it the web build fails
+# with "wasm32-unknown-unknown targets are not supported by default".
+[target.wasm32-unknown-unknown]
+rustflags = ['--cfg', 'getrandom_backend="wasm_js"']

Cargo.lock

@@ -24,6 +24,7 @@ dependencies = [
  "env_logger",
  "flate2",
  "fontdb",
+ "getrandom 0.3.4",
  "glam 0.33.0",
  "iced",
  "image",

Cargo.toml

@@ -24,7 +24,9 @@ solid3d = ["dep:truck-meshalgo", "dep:truck-shapeops", "dep:lzma-sys"]
 [dependencies]
 # Stable, dependency-free add-on contract (manifest + ribbon/CadModule types).
 # Plugin authors target this crate's semver, not OpenCADStudio internals.
-ocs_plugin_api = { path = "crates/ocs_plugin_api", features = ["host"] }
+# The `host` feature (out-of-process plugin runtime: interprocess, libloading,
+# memmap2, rkyv) is native-only — see the per-target sections below; the web
+# build gets the dependency-free manifest/ribbon contract.
 # vtkio (pulled in transitively via truck-meshalgo) depends on xz2 → lzma-sys,
 # which by default links the system liblzma dynamically. On macOS that bakes a
 # Homebrew dylib path (/opt/homebrew/.../liblzma.5.dylib) into the binary, so
@@ -44,7 +46,6 @@ clap = { version = "4", features = ["derive"] }
 # Opt-in logging via --log / RUST_LOG (surfaces wgpu / iced / winit diagnostics).
 env_logger = "0.11"
 acadrust = "0.3.4"
-printpdf = "0.9.1"
 flate2 = "1"
 image = { version = "0.25", default-features = false, features = ["png", "jpeg", "bmp", "tiff"] }
 inventory = "0.3"
@@ -80,14 +81,25 @@ windows-sys = { version = "0.61", features = ["Win32_UI_Shell", "Win32_UI_Window
 acadrust = { git = "https://github.com/HakanSeven12/acadrust", branch = "main" }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
+# Native enables the plugin host runtime (out-of-process plugins).
+ocs_plugin_api = { path = "crates/ocs_plugin_api", features = ["host"] }
 rayon = "1"
 open = "5"
+# PDF export / printing. Native-only: printpdf pulls a wasm-incompatible
+# `memchr` (1.0.2) via lopdf → nom_locate, and the web build has no filesystem.
+printpdf = "0.9.1"
 ureq = { version = "3", default-features = false, features = ["rustls"] }
 # Parse the GitHub Releases API response for the plugin marketplace.
 serde_json = "1"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
+# Web gets the dependency-free manifest/ribbon contract only (no plugin host).
+ocs_plugin_api = { path = "crates/ocs_plugin_api" }
 console_error_panic_hook = "0.1"
+# ahash (via acadrust) pulls getrandom 0.3, which needs the `wasm_js` backend
+# enabled to support wasm32-unknown-unknown (plus the matching rustflag in
+# .cargo/config.toml).
+getrandom = { version = "0.3", features = ["wasm_js"] }
 wasm-bindgen = "0.2"
 # fetch() returns a JS Promise; bridge it to a Rust future for the per-script
 # web font loader (#141).

src/io/pdf_export.rs

@@ -9,15 +9,43 @@
 // drawing origin at the paper origin.
 
 use crate::io::plot_style::PlotStyleTable;
-use crate::scene::model::hatch_model::{HatchModel, HatchPattern};
+use crate::scene::model::hatch_model::HatchModel;
+#[cfg(not(target_arch = "wasm32"))]
+use crate::scene::model::hatch_model::HatchPattern;
 use crate::scene::WireModel;
+#[cfg(not(target_arch = "wasm32"))]
 use printpdf::{
     Color, Line, LineCapStyle, LineJoinStyle, LinePoint, Mm, Op, PaintMode, PdfDocument, PdfPage,
     PdfSaveOptions, Point, Polygon, PolygonRing, Pt, Rgb, WindingOrder,
 };
+#[cfg(not(target_arch = "wasm32"))]
 use std::io::Write;
 use std::path::Path;
 
+// The web build has no `printpdf` (it pulls a wasm-incompatible `memchr` via
+// lopdf → nom_locate) and no filesystem, so PDF export is native-only; the web
+// build gets these stubs so the call sites still compile.
+#[cfg(target_arch = "wasm32")]
+pub fn export_pdf(
+    _wires: &[WireModel],
+    _hatches: &[HatchModel],
+    _wipeouts: &[HatchModel],
+    _paper_w: f64,
+    _paper_h: f64,
+    _offset_x: f32,
+    _offset_y: f32,
+    _rotation_deg: i32,
+    _path: &Path,
+    _plot_style: Option<&PlotStyleTable>,
+) -> Result<(), String> {
+    Err("PDF export is not available in the web version.".into())
+}
+
+#[cfg(target_arch = "wasm32")]
+pub async fn pick_pdf_path_owned(_stem: String) -> Option<std::path::PathBuf> {
+    None
+}
+
 // ── Public entry point ────────────────────────────────────────────────────
 
 /// Export `wires` to a PDF file.
@@ -26,6 +54,7 @@ use std::path::Path;
 /// - `offset_x` / `offset_y`: added to every wire coordinate so the drawing
 ///   origin maps to the bottom-left corner of the page.
 /// - `rotation_deg`: 0 | 90 | 180 | 270 — rotates the entire drawing on the page.
+#[cfg(not(target_arch = "wasm32"))]
 pub fn export_pdf(
     wires: &[WireModel],
     hatches: &[HatchModel],
@@ -54,6 +83,7 @@ pub fn export_pdf(
 }
 
 /// Show a PDF save-file dialog and return the chosen path (or None if cancelled).
+#[cfg(not(target_arch = "wasm32"))]
 pub async fn pick_pdf_path_owned(stem: String) -> Option<std::path::PathBuf> {
     rfd::AsyncFileDialog::new()
         .set_title("Export as PDF")
@@ -67,6 +97,7 @@ pub async fn pick_pdf_path_owned(stem: String) -> Option<std::path::PathBuf> {
 
 // ── PDF builder ───────────────────────────────────────────────────────────
 
+#[cfg(not(target_arch = "wasm32"))]
 fn build_pdf(
     wires: &[WireModel],
     hatches: &[HatchModel],
@@ -235,6 +266,7 @@ fn build_pdf(
     doc.save(&PdfSaveOptions::default(), &mut warnings)
 }
 
+#[cfg(not(target_arch = "wasm32"))]
 fn flush_line(ops: &mut Vec<Op>, pts: &[LinePoint]) {
     if pts.len() < 2 {
         return;
@@ -252,6 +284,7 @@ fn flush_line(ops: &mut Vec<Op>, pts: &[LinePoint]) {
 /// rings so islands and holes render correctly under the even-odd rule.
 /// Mirrors `scene::paper_canvas::draw_hatch`: solid → fill, pattern → outline,
 /// gradient → solid fill of the averaged colour.
+#[cfg(not(target_arch = "wasm32"))]
 fn emit_hatch(ops: &mut Vec<Op>, hatch: &HatchModel, ox: f32, oy: f32) {
     if hatch.boundary.is_empty() {
         return;

src/io/print_to_printer.rs

@@ -7,15 +7,34 @@
 //
 // The function is async so the UI remains responsive while the job is queued.
 
+#[cfg(not(target_arch = "wasm32"))]
 use crate::io::pdf_export;
 use crate::io::plot_style::PlotStyleTable;
 use crate::scene::model::hatch_model::HatchModel;
 use crate::scene::WireModel;
 
+// Printing routes through the native PDF pipeline + the OS print command, so it
+// is native-only; the web build gets a stub so the call site still compiles.
+#[cfg(target_arch = "wasm32")]
+pub async fn print_wires(
+    _wires: Vec<WireModel>,
+    _hatches: Vec<HatchModel>,
+    _wipeouts: Vec<HatchModel>,
+    _paper_w: f64,
+    _paper_h: f64,
+    _offset_x: f32,
+    _offset_y: f32,
+    _rotation_deg: i32,
+    _plot_style: Option<PlotStyleTable>,
+) -> Result<String, String> {
+    Err("Printing is not available in the web version.".into())
+}
+
 /// Render `wires` (plus hatch / wipeout fills) to a temp PDF and dispatch it
 /// to the default system printer.
 ///
 /// Returns `Ok(printer_name)` on success or `Err(message)` on failure.
+#[cfg(not(target_arch = "wasm32"))]
 pub async fn print_wires(
     wires: Vec<WireModel>,
     hatches: Vec<HatchModel>,
@@ -47,6 +66,7 @@ pub async fn print_wires(
 }
 
 /// Platform-specific dispatch of a PDF path to the system printer.
+#[cfg(not(target_arch = "wasm32"))]
 fn dispatch_to_printer(path: &std::path::Path) -> Result<String, String> {
     #[cfg(target_os = "windows")]
     {