fix(gui): resolve PartDesign toolbars and breadcrumb when editing body inside assembly

When double-clicking a PartDesign Body inside an Assembly, the editing
context resolver failed to show PartDesign toolbars or a proper
breadcrumb. Three root causes:

1. Priority preemption: assembly.edit (priority 90) always matched
   because the Assembly VP remained in edit mode, blocking all
   PartDesign contexts (priorities 30-40).

2. Wrong active-object key: PartDesign matchers only queried the
   "part" active object, but ViewProviderBody::toggleActiveBody()
   sets "part" to the containing App::Part (which is the Assembly
   itself). The Body is set under "pdbody", which was never queried.

3. Missing refresh trigger: ActiveObjectList::setObject() fires
   Document::signalActivatedViewProvider, but EditingContextResolver
   had no connection to it, so setActiveObject("pdbody", body) never
   triggered a context re-resolve.

Changes:
- Forward signalActivatedViewProvider from Gui::Document to
  Gui::Application (same pattern as signalInEdit/signalResetEdit)
- Connect EditingContextResolver to the new application-level signal
- Add getActivePdBodyObject() helper querying the "pdbody" key
- Add partdesign.in_assembly context (priority 95) that matches when
  a Body is active pdbody while an Assembly is in edit
- Update partdesign.body and partdesign.feature matchers to check
  pdbody before falling back to the part key
- Add Assembly > Body breadcrumb with Blue > Mauve coloring
- Update label resolution to prefer pdbody name

src/Gui/Application.cpp

@@ -1046,6 +1046,9 @@ void Application::slotNewDocument(const App::Document& Doc, bool isMainDoc)
     );
     pDoc->signalInEdit.connect(std::bind(&Gui::Application::slotInEdit, this, sp::_1));
     pDoc->signalResetEdit.connect(std::bind(&Gui::Application::slotResetEdit, this, sp::_1));
+    pDoc->signalActivatedViewProvider.connect(
+        std::bind(&Gui::Application::slotActivatedViewProvider, this, sp::_1, sp::_2)
+    );
     // NOLINTEND
 
     signalNewDocument(*pDoc, isMainDoc);
@@ -1352,6 +1355,12 @@ void Application::slotResetEdit(const Gui::ViewProviderDocumentObject& vp)
     this->signalResetEdit(vp);
 }
 
+void Application::slotActivatedViewProvider(
+    const Gui::ViewProviderDocumentObject* vp, const char* name)
+{
+    this->signalActivatedViewProvider(vp, name);
+}
+
 void Application::onLastWindowClosed(Gui::Document* pcDoc)
 {
     try {

src/Gui/Application.h

@@ -153,6 +153,9 @@ public:
     fastsignals::signal<void(const Gui::ViewProviderDocumentObject&)> signalInEdit;
     /// signal on leaving edit mode
     fastsignals::signal<void(const Gui::ViewProviderDocumentObject&)> signalResetEdit;
+    /// signal on activated view-provider (active-object change, e.g. "pdbody", "part")
+    fastsignals::signal<void(const Gui::ViewProviderDocumentObject*, const char*)>
+        signalActivatedViewProvider;
     /// signal on changing user edit mode
     fastsignals::signal<void(int)> signalUserEditModeChanged;
     //@}
@@ -174,6 +177,7 @@ protected:
     void slotActivatedObject(const ViewProvider&);
     void slotInEdit(const Gui::ViewProviderDocumentObject&);
     void slotResetEdit(const Gui::ViewProviderDocumentObject&);
+    void slotActivatedViewProvider(const Gui::ViewProviderDocumentObject*, const char*);
 
 public:
     /// message when a GuiDocument is about to vanish

src/Gui/EditingContext.cpp

@@ -121,6 +121,9 @@ EditingContextResolver::EditingContextResolver()
     app.signalActiveDocument.connect([this](const Document& doc) { onActiveDocument(doc); });
     app.signalActivateView.connect([this](const MDIView* view) { onActivateView(view); });
     app.signalActivateWorkbench.connect([this](const char*) { refresh(); });
+    app.signalActivatedViewProvider.connect(
+        [this](const ViewProviderDocumentObject*, const char*) { refresh(); }
+    );
 }
 
 EditingContextResolver::~EditingContextResolver()
@@ -172,6 +175,23 @@ static App::DocumentObject* getActivePartObject()
     return view->getActiveObject<App::DocumentObject*>("part");
 }
 
+// ---------------------------------------------------------------------------
+// Helper: get the active "pdbody" object from the active view
+// ---------------------------------------------------------------------------
+
+static App::DocumentObject* getActivePdBodyObject()
+{
+    auto* guiDoc = Application::Instance->activeDocument();
+    if (!guiDoc) {
+        return nullptr;
+    }
+    auto* view = guiDoc->getActiveView();
+    if (!view) {
+        return nullptr;
+    }
+    return view->getActiveObject<App::DocumentObject*>("pdbody");
+}
+
 // ---------------------------------------------------------------------------
 // Helper: get the label of the active "part" object
 // ---------------------------------------------------------------------------
@@ -213,6 +233,34 @@ static QString getInEditLabel()
 
 void EditingContextResolver::registerBuiltinContexts()
 {
+    // --- PartDesign body active inside an assembly (supersedes assembly.edit) ---
+    registerContext({
+        /*.id =*/QStringLiteral("partdesign.in_assembly"),
+        /*.labelTemplate =*/QStringLiteral("Body: {name}"),
+        /*.color =*/QLatin1String(CatppuccinMocha::Mauve),
+        /*.toolbars =*/
+        {QStringLiteral("Part Design Helper Features"),
+         QStringLiteral("Part Design Modeling Features"),
+         QStringLiteral("Part Design Dress-Up Features"),
+         QStringLiteral("Part Design Transformation Features"),
+         QStringLiteral("Sketcher")},
+        /*.priority =*/95,
+        /*.match =*/
+        []() {
+            auto* body = getActivePdBodyObject();
+            if (!body || !objectIsDerivedFrom(body, "PartDesign::Body")) {
+                return false;
+            }
+            // Only match when we're inside an assembly edit session
+            auto* doc = Application::Instance->activeDocument();
+            if (!doc) {
+                return false;
+            }
+            auto* vp = doc->getInEdit();
+            return vp && vpObjectIsDerivedFrom(vp, "Assembly::AssemblyObject");
+        },
+    });
+
     // --- Sketcher edit (highest priority — VP in edit) ---
     registerContext({
         /*.id =*/QStringLiteral("sketcher.edit"),
@@ -272,7 +320,10 @@ void EditingContextResolver::registerBuiltinContexts()
         /*.priority =*/40,
         /*.match =*/
         []() {
-            auto* obj = getActivePartObject();
+            auto* obj = getActivePdBodyObject();
+            if (!obj) {
+                obj = getActivePartObject();
+            }
             if (!obj || !objectIsDerivedFrom(obj, "PartDesign::Body")) {
                 return false;
             }
@@ -301,7 +352,10 @@ void EditingContextResolver::registerBuiltinContexts()
         /*.priority =*/30,
         /*.match =*/
         []() {
-            auto* obj = getActivePartObject();
+            auto* obj = getActivePdBodyObject();
+            if (!obj) {
+                obj = getActivePartObject();
+            }
             return obj && objectIsDerivedFrom(obj, "PartDesign::Body");
         },
     });
@@ -488,6 +542,13 @@ EditingContext EditingContextResolver::resolve() const
             if (label.contains(QStringLiteral("{name}"))) {
                 // For edit-mode contexts, use the in-edit object name
                 QString name = getInEditLabel();
+                if (name.isEmpty()) {
+                    // Try pdbody first for PartDesign contexts
+                    auto* bodyObj = getActivePdBodyObject();
+                    if (bodyObj) {
+                        name = QString::fromUtf8(bodyObj->Label.getValue());
+                    }
+                }
                 if (name.isEmpty()) {
                     name = getActivePartLabel();
                 }
@@ -548,6 +609,25 @@ QStringList EditingContextResolver::buildBreadcrumb(const EditingContext& ctx) c
         return crumbs;
     }
 
+    // Assembly > Body breadcrumb for in-assembly part editing
+    if (ctx.id == QStringLiteral("partdesign.in_assembly")) {
+        auto* guiDoc = Application::Instance->activeDocument();
+        if (guiDoc) {
+            auto* vp = guiDoc->getInEdit();
+            if (vp) {
+                auto* vpd = dynamic_cast<ViewProviderDocumentObject*>(vp);
+                if (vpd && vpd->getObject()) {
+                    crumbs << QString::fromUtf8(vpd->getObject()->Label.getValue());
+                }
+            }
+        }
+        auto* body = getActivePdBodyObject();
+        if (body) {
+            crumbs << QString::fromUtf8(body->Label.getValue());
+        }
+        return crumbs;
+    }
+
     // Always start with the active part/body/assembly label
     QString partLabel = getActivePartLabel();
     if (!partLabel.isEmpty()) {
@@ -582,6 +662,14 @@ QStringList EditingContextResolver::buildBreadcrumbColors(const EditingContext&
 {
     QStringList colors;
 
+    if (ctx.id == QStringLiteral("partdesign.in_assembly")) {
+        for (int i = 0; i < ctx.breadcrumb.size(); ++i) {
+            colors << (i == 0 ? QLatin1String(CatppuccinMocha::Blue)
+                              : QLatin1String(CatppuccinMocha::Mauve));
+        }
+        return colors;
+    }
+
     if (ctx.breadcrumb.size() <= 1) {
         colors << ctx.color;
         return colors;