feat(wasm-eh): migrate the WASM build to native wasm exceptions (+ 3D viewer default-on)

Replace the legacy Emscripten JS-exceptions model with native wasm-EH (legacy
encoding) across the whole build, keeping Asyncify coroutines working via a
from-source Binaryen --hoist-cpp-catches pre-pass. Net result: native-EH is the
only build mode, the 3D viewer is on by default, and pcbnew shrinks substantially.

Highlights:
- Binaryen submodule everywhere + --hoist-cpp-catches integration in apply-asyncify;
  post-link Asyncify covers every app wasm (not just standalone test wasm).
- Build deps (incl. OpenCASCADE without OCC_CONVERT_SIGNALS) and all KiCad apps
  with -fwasm-exceptions; emscripten_sleep added to the post-link asyncify-imports.
- libcontext fiber entry wired under native exceptions; while-loop main loop +
  currData shim injected into all wx apps.
- Native-EH collab apply fixed: DEBUG-define the embind TU + match all out-of-CMake
  C++ TUs' ABI flags to the core, fixing the vtable-layout skew / mis-dispatch.
- 3D viewer enabled by default (real raytracer linked, not the stub).
- Retire the EH-spike scaffolding; flip the asyncify-races ablation pins to
  shim-redundancy pins (native-EH stays clean with the legacy shims ablated).
- Fix the asyncify-races quiescence check to not require Asyncify.currData==0:
  under the native-EH per-frame-yield top loop the main stack is asyncify-suspended
  every frame, so currData legitimately churns (a freed-but-not-yet-nulled buffer,
  not a leak). Refresh the pcbnew toolbar screenshot baseline for the new kicad.
- CI: drop the obsolete binaryen_version input/env (the build uses the binaryen
  submodule fork's wasm-opt, not a version download); key the wasm-output cache on
  the binaryen submodule SHA instead.

Bumps the wxwidgets + binaryen submodules to their squashed feature commits.

Validated green: all 7 apps native-EH (real 3D in pcbnew); KiCad e2e 63/63
Firefox + Chromium (3D viewer renders); wx 336; coroutine 34/34 both engines;
asyncify 7/7 both engines.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

scripts/build-wasm-test.sh

@@ -92,6 +92,25 @@ if [ "$CLEAN_BUILD" = "1" ]; then
     make -f Makefile.wasm clean 2>/dev/null || true
 fi
 
+# Native wasm-EH is the only build mode. The emsdk-bundled Binaryen v121 crashes asyncifying wasm-EH,
+# so we stub the in-link Asyncify and run --hoist-cpp-catches + --asyncify post-link on the Binaryen
+# submodule (version_130 + hoist pass) via apply-asyncify.sh.
+EMSDK_WASM_OPT="$PROJECT_ROOT/tools/emsdk/upstream/bin/wasm-opt"
+WASMOPT_STUB="$PROJECT_ROOT/wasm/stubs/wasm-opt-stub.sh"
+_eh_restore_wasmopt() { [ -f "${EMSDK_WASM_OPT}.ehbak" ] && mv -f "${EMSDK_WASM_OPT}.ehbak" "${EMSDK_WASM_OPT}"; }
+EH_MARKER="$(mktemp)"   # created before the build so 'find -newer' below selects freshly-linked apps
+echo ""
+echo "=== Building the Binaryen submodule (version_130 + hoist pass) ==="
+# One binaryen everywhere: the submodule fork is version_130 (asyncify unchanged) + our hoist
+# pass, so the same binary does --hoist-cpp-catches AND --asyncify/-O2. No separate v130 clone.
+export HOIST_WASMOPT="$("$SCRIPT_DIR/binaryen-hoist-pass/build-wasm-opt.sh")"
+export V130_WASMOPT="$HOIST_WASMOPT"
+echo "  submodule wasm-opt: $HOIST_WASMOPT"
+echo "Stubbing in-link Asyncify (will run post-link instead)..."
+cp "$EMSDK_WASM_OPT" "${EMSDK_WASM_OPT}.ehbak"
+cp "$WASMOPT_STUB" "$EMSDK_WASM_OPT"; chmod +x "$EMSDK_WASM_OPT"
+trap _eh_restore_wasmopt EXIT
+
 # Build (pass DEBUG flag if requested). App links are independent, so honor
 # JOBS/PARALLEL_JOBS from env.sh (each emcc link is slow due to Asyncify).
 if [ "$DEBUG_BUILD" = "1" ]; then
@@ -99,6 +118,38 @@ if [ "$DEBUG_BUILD" = "1" ]; then
 else
     make -j"${JOBS:-1}" -f Makefile.wasm "$MAKE_TARGET"
 fi
+make_rc=$?
+if [ "$make_rc" -ne 0 ]; then
+    # Fail loudly. Silently continuing to the post-link leaves the freshly-linked apps
+    # asyncify-stubbed / un-injected, which looks like mass test failures rather than a build
+    # error. (The EXIT trap restores the stubbed emsdk wasm-opt in the native-EH build.)
+    echo "" >&2
+    echo "ERROR: make failed (exit $make_rc); aborting before the post-link step." >&2
+    exit "$make_rc"
+fi
+
+# Inject the dyncall + handlesleep currData shims into every freshly-linked app. The
+# handlesleep currData save/restore (Emscripten #9153) is needed: without it a rewind that
+# resumes through a fresh wasm re-entry hits _asyncify_start_rewind(null) -> "memory access out
+# of bounds" — e.g. a context-menu pick while the main loop is parked. The Makefile only injects
+# it for the coroutine apps; inject-dyncall-shims.sh is idempotent (skips an already-shimmed glue),
+# so re-running it here is safe. The .wasm gets post-link hoist + asyncify first.
+_eh_restore_wasmopt; trap - EXIT
+echo ""
+echo "=== Post-link --hoist-cpp-catches + --asyncify ==="
+while IFS= read -r w; do
+    "$SCRIPT_DIR/common/apply-asyncify.sh" --no-removelist "$w"
+    js="${w%.wasm}.js"
+    if [ -f "$js" ]; then
+        ( cd "$(dirname "$js")" && "$SCRIPT_DIR/common/inject-dyncall-shims.sh" "$(basename "$js")" )
+    fi
+# Match EVERY freshly-linked app wasm, not just standalone/*/*_test.wasm: the main demo
+# (apps/minimal_test.wasm) is at the apps/ root, and the coroutine-pthread repros + wxpt app
+# are *_repro*.wasm / *_wxpt.wasm. The old '*_test.wasm under standalone' filter silently
+# skipped all of those, so under native wasm-EH they never got hoist+asyncify and crashed at
+# runtime with "asyncify_start_unwind not found".
+done < <(find "$WASM_APP_DIR" -name '*.wasm' -newer "$EH_MARKER")
+rm -f "$EH_MARKER"
 
 echo ""
 echo "=== Build complete ==="