Fix KiCad WASM build and runtime errors

Build improvements:
- Change -O0 to -O1 to fix "local count too large" asyncify error
- Add wasm-emscripten-finalize to host (Docker OOMs on large WASM)
- Use -gseparate-dwarf for smaller main binary with debug info
- Build native protoc for code generation
- Add more functions to asyncify removelist

Runtime fixes:
- Add inject-dyncall-shims.sh to fix "dynCall_* is not defined" in Emscripten 4.x
- Update wxwidgets with browserInfo.name fix

New stubs and bindings:
- Add Embind bindings for JavaScript interop
- Add stubs for scripting, API plugin, PCB frame, navlib

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

wasm/stubs/scripting_stub.cpp

@@ -0,0 +1,65 @@
+/*
+ * Scripting stubs for KiCad WASM build
+ * Python scripting is not available in WASM
+ *
+ * These stubs provide implementations for methods declared in pcb_scripting_tool.h
+ * that are called from panel_pcbnew_action_plugins.cpp
+ */
+
+#include <python/scripting/pcb_scripting_tool.h>
+
+// Constructor/Destructor implementations
+SCRIPTING_TOOL::SCRIPTING_TOOL() :
+    PCB_TOOL_BASE( "pcbnew.ScriptingTool" )
+{
+}
+
+SCRIPTING_TOOL::~SCRIPTING_TOOL()
+{
+}
+
+// Virtual method implementations
+bool SCRIPTING_TOOL::Init()
+{
+    return true;
+}
+
+void SCRIPTING_TOOL::Reset( RESET_REASON aReason )
+{
+    (void)aReason;
+}
+
+// Static method implementations - these are called from panel_pcbnew_action_plugins.cpp
+void SCRIPTING_TOOL::ReloadPlugins()
+{
+    // No-op: Python plugins not available in WASM
+}
+
+void SCRIPTING_TOOL::ShowPluginFolder()
+{
+    // No-op: Plugin folder not accessible in WASM
+}
+
+// Private method implementations
+int SCRIPTING_TOOL::reloadPlugins( const TOOL_EVENT& aEvent )
+{
+    (void)aEvent;
+    return 0;
+}
+
+int SCRIPTING_TOOL::showPluginFolder( const TOOL_EVENT& aEvent )
+{
+    (void)aEvent;
+    return 0;
+}
+
+void SCRIPTING_TOOL::setTransitions()
+{
+    // No transitions: scripting not available
+}
+
+// Private static method - must be provided since it's declared in header
+void SCRIPTING_TOOL::callLoadPlugins()
+{
+    // No-op: Python not available in WASM
+}