Extract set-signal-type into core; add it to the wx GUI.

Fourth editing op into the wx frontend. Extract the type-name parse + apply
into core/app/edit.hpp::set_signal_type(Signal*, name) -> {ok, error, type},
failing without mutation on an unrecognised name. The interactive sigtype modal
keeps its own SignalType-cycling path (different interaction, trivial mutation).

The TUI `set-signal-type` command now renders that result (output unchanged).
The wx GUI gains Edit ▸ Set signal type…: a shared PickModule() helper (PickPart
now builds on it) + inline signal choice + a power/gnd/other dropdown, then the
core op, logged as "module/signal: signal type = …" and reflected.

tests/test_edit.cpp: name parsed and applied; unknown name refused without
mutation. 387 core assertions green; tui + wx build clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/frontends/wx/wx_frame.cpp

@@ -35,6 +35,7 @@ enum {
     ID_EXPORT,
     ID_SET_CONNECTOR_TYPE,
     ID_ATTACH_BSDL,
+    ID_SET_SIGNAL_TYPE,
     ID_CONNECT,
     ID_VERIFY,
     ID_QUIT,
@@ -61,6 +62,7 @@ EssimFrame::EssimFrame(WxFrontend &fe)
     auto *edit = new wxMenu;
     edit->Append(ID_SET_CONNECTOR_TYPE, "Set &connector type…\tCtrl-T");
     edit->Append(ID_ATTACH_BSDL, "Attach &BSDL…\tCtrl-B");
+    edit->Append(ID_SET_SIGNAL_TYPE, "Set &signal type…\tCtrl-G");
     edit->AppendSeparator();
     edit->Append(ID_CONNECT, "C&onnect parts…\tCtrl-O");
 
@@ -107,6 +109,7 @@ EssimFrame::EssimFrame(WxFrontend &fe)
     Bind(wxEVT_MENU, &EssimFrame::OnExport,  this, ID_EXPORT);
     Bind(wxEVT_MENU, &EssimFrame::OnSetConnectorType, this, ID_SET_CONNECTOR_TYPE);
     Bind(wxEVT_MENU, &EssimFrame::OnAttachBsdl, this, ID_ATTACH_BSDL);
+    Bind(wxEVT_MENU, &EssimFrame::OnSetSignalType, this, ID_SET_SIGNAL_TYPE);
     Bind(wxEVT_MENU, &EssimFrame::OnConnect, this, ID_CONNECT);
     Bind(wxEVT_MENU, &EssimFrame::OnVerify,  this, ID_VERIFY);
     Bind(wxEVT_MENU, &EssimFrame::OnQuit,    this, ID_QUIT);
@@ -261,23 +264,26 @@ void EssimFrame::OnExport(wxCommandEvent &) {
     }
 }
 
-Part *EssimFrame::PickPart(const wxString &caption) {
+Module *EssimFrame::PickModule(const wxString &caption) {
     System *sys = fe_.system();
     if (!sys || sys->modules()->size() == 0) {
         wxMessageBox("No modules loaded.", caption,
                      wxOK | wxICON_INFORMATION, this);
         return nullptr;
     }
-
     std::vector<std::string> mods;
     for (auto &mkv : *sys->modules()) mods.push_back(mkv.first);
     std::sort(mods.begin(), mods.end());
-    wxArrayString mchoices;
-    for (const auto &m : mods) mchoices.Add(wx(m));
-    int mi = wxGetSingleChoiceIndex("Module:", caption, mchoices, this);
+    wxArrayString choices;
+    for (const auto &m : mods) choices.Add(wx(m));
+    int mi = wxGetSingleChoiceIndex("Module:", caption, choices, this);
     if (mi < 0) return nullptr;
-    Module *m = sys->modules()->get(mods[mi]);
+    return sys->modules()->get(mods[mi]);
+}
 
+Part *EssimFrame::PickPart(const wxString &caption) {
+    Module *m = PickModule(caption);
+    if (!m) return nullptr;
     if (m->size() == 0) {
         wxMessageBox("That module has no parts.", caption,
                      wxOK | wxICON_INFORMATION, this);
@@ -286,13 +292,14 @@ Part *EssimFrame::PickPart(const wxString &caption) {
     std::vector<std::string> parts;
     for (auto &pkv : *m) parts.push_back(pkv.first);
     std::sort(parts.begin(), parts.end());
-    wxArrayString pchoices;
-    for (const auto &p : parts) pchoices.Add(wx(p));
-    int pi = wxGetSingleChoiceIndex("Part:", caption, pchoices, this);
+    wxArrayString choices;
+    for (const auto &p : parts) choices.Add(wx(p));
+    int pi = wxGetSingleChoiceIndex("Part:", caption, choices, this);
     if (pi < 0) return nullptr;
     return m->get(parts[pi]);
 }
 
+
 void EssimFrame::OnSetConnectorType(wxCommandEvent &) {
     Part *p = PickPart();
     if (!p) return;
@@ -378,6 +385,39 @@ void EssimFrame::OnConnect(wxCommandEvent &) {
     RebuildModelView();
 }
 
+void EssimFrame::OnSetSignalType(wxCommandEvent &) {
+    Module *m = PickModule("Set signal type");
+    if (!m) return;
+    if (m->signals->size() == 0) {
+        wxMessageBox("That module has no signals.", "Set signal type",
+                     wxOK | wxICON_INFORMATION, this);
+        return;
+    }
+    std::vector<std::string> sigs;
+    for (auto &skv : *m->signals) sigs.push_back(skv.first);
+    std::sort(sigs.begin(), sigs.end());
+    wxArrayString schoices;
+    for (const auto &s : sigs) schoices.Add(wx(s));
+    int si = wxGetSingleChoiceIndex("Signal:", "Set signal type", schoices, this);
+    if (si < 0) return;
+    Signal *sig = m->signals->get(sigs[si]);
+
+    static const wxString types[] = {"power", "gnd", "other"};
+    int ti = wxGetSingleChoiceIndex("Type:", "Set signal type",
+                                    WXSIZEOF(types), types, this);
+    if (ti < 0) return;
+
+    app::SetSignalTypeResult r = app::set_signal_type(sig, types[ti].ToStdString());
+    if (!r.ok) {
+        Log(wx(r.error));
+        wxMessageBox(wx(r.error), "Set signal type", wxOK | wxICON_ERROR, this);
+        return;
+    }
+    Log(wxString::Format("%s/%s: signal type = %s", wx(m->name), wx(sig->name),
+                         wx(signal_type_name(r.type))));
+    RebuildModelView();
+}
+
 void EssimFrame::OnVerify(wxCommandEvent &) {
     app::VerifyReport r = app::verify(fe_.system());