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/common/shims/dyncall-binding.js.tmpl

@@ -1,25 +0,0 @@
-// Template for one dynCall_<sig> binding. Placeholders substituted per signature
-// by inject-dyncall-shims.sh:  @SIG@ = signature, @ARGS@ = "index, a0, a1, ...",
-// @CALLARGS@ = "a0, a1, ..." (the args without the function-pointer index).
-//
-// Binds the bare name to the REAL asyncify-instrumented wasm export
-// (wasmExports["dynCall_<sig>"], present because the build links -sDYNCALLS=1).
-// Falls back to getWasmTableEntry if no such export exists, OR if the instrumented
-// trampoline traps with "indirect call signature mismatch": post-asyncify+O2 the
-// trampoline can call_indirect with a stale type for some table indices even though
-// the table entry itself is valid (hit by programmatic editor edits, e.g. eeschema
-// SCH_ITEM::Move via invoke_vii — see features/yjs-bridge/0003). The direct
-// getWasmTableEntry call uses the correct per-entry signature and succeeds. Only the
-// mismatch trap is caught; the Asyncify unwind sentinel and real exceptions re-throw,
-// so instrumentation/unwind still work for every normal indirect call.
-function dynCall_@SIG@(@ARGS@) {
-  var f = (typeof wasmExports !== 'undefined') && wasmExports["dynCall_@SIG@"];
-  if (f) {
-    try { return f(@ARGS@); }
-    catch (_dce) {
-      if (!(_dce instanceof WebAssembly.RuntimeError) || !/signature mismatch/.test(_dce.message))
-        throw _dce;
-    }
-  }
-  return getWasmTableEntry(index)(@CALLARGS@);
-}