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
