feat(read-only-viewer): editor viewer mode + kicadSetReadOnly binding

Anonymous / non-member sessions open PUBLIC projects as read-only viewers.

- kicadSetReadOnly(bool) embind (merged kicad_editor + pcbnew/eeschema/
  pl_editor TUs): sets the PCBJAM_READ_ONLY flag + Prj().SetReadOnly (greys
  the setup dialogs). Polls until the frame exists.
- read-only-mode.ts: resolveReadOnly(access, win) — server `access:"read"` or
  ?readonly=1 (narrow-only; no ?readonly=0). ToolPage threads it in, omits
  saveBytes (MEMFS-only saves).
- WasmTool: chrome force-hidden with a "View only" pill (toggle + Cmd+\
  disabled), presence/cross-app/comments/drift skipped, save-driven room
  writers unregistered, wasm frame locked via kicadSetReadOnly failing CLOSED
  (stale bundle → boot error, never a writable frame).
- collab: bindKicadCollab {readOnly} — inert DOWN hook, never seeds a room;
  UP observer + adopt stay live so peer edits render. index.ts / sheet-manager
  thread readOnly + drop initial awareness (invisible observer).
- Reference backend emits access:"write".

Bumps kicad + web/pcbjam-shared to the read-only-viewer commits.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012DN9py5GuPdExaaFzE4k27

wasm/bindings/pcbnew_embind.cpp

@@ -44,6 +44,8 @@
 #include <tool/coroutine.h>
 #include <tool/tool_manager.h>
 #include <pcbjam_remote_lock.h>
+#include <pcbjam_read_only.h>
+#include <project.h>
 #include <view/view.h>
 #include <view/view_overlay.h>
 #include <pcb_draw_panel_gal.h>
@@ -93,6 +95,24 @@ bool kicadOpenFile( std::string path )
     return frame->OpenProjectFiles(
             std::vector<wxString>( 1, wxString::FromUTF8( path.c_str() ) ) );
 }
+
+// Read-only viewer lock (read-only-viewer): flips the process-global
+// PCBJAM_READ_ONLY flag consumed by TOOL_MANAGER (view-only action allowlist)
+// and the selection tools (nothing selectable), and mirrors it onto the
+// project so the setup dialogs grey out. Returns false until the editor frame
+// exists so JS polls; the shell fails CLOSED if it never applies.
+bool kicadSetReadOnly( bool aReadOnly )
+{
+    KIWAY_PLAYER* frame =
+            wxTheApp ? dynamic_cast<KIWAY_PLAYER*>( wxTheApp->GetTopWindow() ) : nullptr;
+
+    if( !frame )
+        return false;
+
+    PCBJAM_READ_ONLY::Set( aReadOnly );
+    frame->Prj().SetReadOnly( aReadOnly );
+    return true;
+}
 #endif // !KICAD_MERGED_EMBIND
 
 // ───────────────────────────── Yjs collaborative bridge ─────────────────────────────
@@ -1980,6 +2000,8 @@ EMSCRIPTEN_BINDINGS(pcbnew) {
     // registered once by kicad_editor_embind.cpp, dispatching on the active frame.
     // Programmatic file open (preferred over UI automation from the web app).
     function("kicadOpenFile", &kicadOpenFile);
+    // Read-only viewer lock (read-only-viewer).
+    function("kicadSetReadOnly", &kicadSetReadOnly);
     // Yjs collaborative bridge entry points (same contract as pl_editor / eeschema).
     function("kicadCollabApply", &pcbCollabApply);
     function("kicadCollabSnapshot", &pcbCollabSnapshot);