feat(web): wire pl_editor + symbol_editor tools (open, wizard-skip, UI)

Add the two newly WASM-ported editors to the web app the same way as the
existing tools:

- pl_editor (drawing-sheet, .kicad_wks): PL_EDITOR_FRAME overrides
  OpenProjectFiles, so it gets the generic kicadOpenFile embind hook
  (wasm/bindings/pl_editor_embind.cpp) for deterministic open. Mapped
  .kicad_wks -> pl_editor in EXTENSION_TOOL.
- symbol_editor (symbol library): SYMBOL_EDIT_FRAME does NOT override
  OpenProjectFiles, so it's treated as file-less (boot standalone, opens
  libraries via its own UI). Added to FILELESS_TOOLS.

Both boot through single_top.cpp's STARTWIZARD, so both seed config to skip the
first-run wizard (TOOL_NEEDS_CONFIG_SEED) and get a /usr/bin/<binary> argv0.

contract: add to TOOLS, plus a TOOL_LABELS map for friendly names. The project
UI now renders file-less launch links generically from FILELESS_TOOLS and
per-file "Open in <label>" links from EXTENSION_TOOL (auto file-type detection),
so adding a tool needs no UI edits.

Verified in-browser: pl_editor opens a .kicad_wks (renders the sheet),
symbol_editor boots wizard-free; both with 0 console errors.

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

wasm/bindings/pl_editor_embind.cpp

@@ -0,0 +1,44 @@
+/*
+ * Embind bindings for KiCad pl_editor (drawing-sheet / page-layout editor) WASM.
+ *
+ * Picked up automatically by scripts/kicad/build-kicad-target.sh when building
+ * the pl_editor app (it compiles wasm/bindings/<app>_embind.cpp if present).
+ */
+
+#ifdef __EMSCRIPTEN__
+#include <emscripten/bind.h>
+#include <kiway_player.h>
+#include <kiway.h>
+#include <vector>
+#include <wx/app.h>
+#include <wx/string.h>
+#include <wx/window.h>
+
+using namespace emscripten;
+
+// Programmatically open a drawing-sheet file (.kicad_wks) in the running editor
+// frame, without UI automation. Mirrors single_top.cpp's MacOpenFile path: the
+// editor frame is the app's top window and is a KIWAY_PLAYER (PL_EDITOR_FRAME
+// overrides OpenProjectFiles). Returns the result of OpenProjectFiles, or false
+// if no frame is available — letting the JS caller fall back to driving
+// File→Open.
+bool kicadOpenFile( std::string path )
+{
+    KIWAY_PLAYER* frame =
+            wxTheApp ? static_cast<KIWAY_PLAYER*>( wxTheApp->GetTopWindow() ) : nullptr;
+
+    if( !frame )
+        return false;
+
+    if( wxWindow* blocking = frame->Kiway().GetBlockingDialog() )
+        blocking->Close( true );
+
+    return frame->OpenProjectFiles(
+            std::vector<wxString>( 1, wxString::FromUTF8( path.c_str() ) ) );
+}
+
+EMSCRIPTEN_BINDINGS(pl_editor) {
+    // Programmatic file open (preferred over UI automation from the web app).
+    function("kicadOpenFile", &kicadOpenFile);
+}
+#endif