feat(gui): implement issues #10 and #12 - LocalFileOrigin and Std_* delegation

Issue #10: Local filesystem origin implementation
- Add openDocumentInteractive() method to FileOrigin interface for UI-based
  file opening (shows file dialog)
- Add saveDocumentAsInteractive() method for UI-based save as
- Implement LocalFileOrigin::openDocumentInteractive() with full file dialog
  support, filter list building, and module handler integration
- Implement LocalFileOrigin::saveDocumentAsInteractive() delegating to
  Gui::Document::saveAs()

Issue #12: Modify Std_* commands to delegate to current origin
- StdCmdNew::activated() now delegates to origin->newDocument() and sets
  up view orientation for the new document
- StdCmdOpen::activated() delegates to origin->openDocumentInteractive()
  with connection state checking for authenticated origins
- StdCmdSave::activated() uses document's owning origin (via findOwningOrigin)
  for save, falling back to saveDocumentAsInteractive if no filename
- StdCmdSaveAs::activated() delegates to origin->saveDocumentAsInteractive()
- Updated isActive() methods to check for active document

The Std_* commands now work seamlessly with both LocalFileOrigin and
SiloOrigin. When Local origin is selected, standard file dialogs appear.
When Silo origin is selected, Silo's search/creation dialogs appear.

Import and Export commands are left unchanged as they operate on document
content rather than document lifecycle.

Closes #10, Closes #12

src/Gui/FileOrigin.cpp

@@ -22,15 +22,23 @@
 
 #include "PreCompiled.h"
 
+#include <algorithm>
+
+#include <QApplication>
+#include <QMessageBox>
+
 #include <App/Application.h>
 #include <App/Document.h>
 #include <App/DocumentObject.h>
 #include <App/PropertyStandard.h>
 
 #include "FileOrigin.h"
+#include "Application.h"
 #include "BitmapFactory.h"
 #include "Document.h"
-#include "Application.h"
+#include "FileDialog.h"
+#include "MainWindow.h"
+#include "SelectModule.h"
 
 
 namespace Gui {
@@ -99,6 +107,86 @@ App::Document* LocalFileOrigin::openDocument(const std::string& identity)
     return App::GetApplication().openDocument(identity.c_str());
 }
 
+App::Document* LocalFileOrigin::openDocumentInteractive()
+{
+    // Build file filter list for Open dialog
+    QString formatList;
+    const char* supported = QT_TR_NOOP("Supported formats");
+    const char* allFiles = QT_TR_NOOP("All files (*.*)");
+    formatList = QObject::tr(supported);
+    formatList += QLatin1String(" (");
+
+    std::vector<std::string> filetypes = App::GetApplication().getImportTypes();
+    // Make sure FCStd is the very first fileformat
+    auto it = std::find(filetypes.begin(), filetypes.end(), "FCStd");
+    if (it != filetypes.end()) {
+        filetypes.erase(it);
+        filetypes.insert(filetypes.begin(), "FCStd");
+    }
+    for (it = filetypes.begin(); it != filetypes.end(); ++it) {
+        formatList += QLatin1String(" *.");
+        formatList += QLatin1String(it->c_str());
+    }
+
+    formatList += QLatin1String(");;");
+
+    std::map<std::string, std::string> FilterList = App::GetApplication().getImportFilters();
+    // Make sure the format name for FCStd is the very first in the list
+    for (auto jt = FilterList.begin(); jt != FilterList.end(); ++jt) {
+        if (jt->first.find("*.FCStd") != std::string::npos) {
+            formatList += QLatin1String(jt->first.c_str());
+            formatList += QLatin1String(";;");
+            FilterList.erase(jt);
+            break;
+        }
+    }
+    for (const auto& filter : FilterList) {
+        formatList += QLatin1String(filter.first.c_str());
+        formatList += QLatin1String(";;");
+    }
+    formatList += QObject::tr(allFiles);
+
+    QString selectedFilter;
+    QStringList fileList = FileDialog::getOpenFileNames(
+        getMainWindow(),
+        QObject::tr("Open Document"),
+        QString(),
+        formatList,
+        &selectedFilter
+    );
+    if (fileList.isEmpty()) {
+        return nullptr;
+    }
+
+    // Load the files with the associated modules
+    SelectModule::Dict dict = SelectModule::importHandler(fileList, selectedFilter);
+    if (dict.isEmpty()) {
+        QMessageBox::critical(
+            getMainWindow(),
+            qApp->translate("StdCmdOpen", "Cannot Open File"),
+            qApp->translate("StdCmdOpen", "Loading the file %1 is not supported").arg(fileList.front())
+        );
+        return nullptr;
+    }
+
+    App::Document* lastDoc = nullptr;
+    for (SelectModule::Dict::iterator it = dict.begin(); it != dict.end(); ++it) {
+        // Set flag indicating that this load/restore has been initiated by the user
+        Application::Instance->setStatus(Gui::Application::UserInitiatedOpenDocument, true);
+
+        Application::Instance->open(it.key().toUtf8(), it.value().toLatin1());
+
+        Application::Instance->setStatus(Gui::Application::UserInitiatedOpenDocument, false);
+
+        lastDoc = App::GetApplication().getActiveDocument();
+
+        Application::Instance->checkPartialRestore(lastDoc);
+        Application::Instance->checkRestoreError(lastDoc);
+    }
+
+    return lastDoc;
+}
+
 bool LocalFileOrigin::saveDocument(App::Document* doc)
 {
     if (!doc) {
@@ -125,4 +213,20 @@ bool LocalFileOrigin::saveDocumentAs(App::Document* doc, const std::string& newI
     return doc->saveAs(newIdentity.c_str());
 }
 
+bool LocalFileOrigin::saveDocumentAsInteractive(App::Document* doc)
+{
+    if (!doc) {
+        return false;
+    }
+
+    // Get Gui document for save dialog
+    Gui::Document* guiDoc = Application::Instance->getDocument(doc);
+    if (!guiDoc) {
+        return false;
+    }
+
+    // Use Gui::Document::saveAs() which handles the file dialog
+    return guiDoc->saveAs();
+}
+
 }  // namespace Gui