Implement session-based language overrides for the viewer

src/teletext/ui.py

@@ -126,6 +126,7 @@ class MainWindow(QMainWindow):
         self.undo_stack = []
         self.redo_stack = []
         self.is_modified = False
+        self.language_overrides = {} # Session-based viewer overrides: (mag, pnum) -> lang_idx
         
         # UI Components
         self.central_widget = QWidget()
@@ -442,6 +443,12 @@ class MainWindow(QMainWindow):
         if action:
             idx = action.data()
             self.canvas.subset_idx = idx
+            
+            # Store session override for the current page (magazine + page number)
+            if self.current_page:
+                key = (self.current_page.magazine, self.current_page.page_number)
+                self.language_overrides[key] = idx
+                
             self.canvas.redraw()
             self.canvas.update()
             self.update_language_label()
@@ -480,6 +487,7 @@ class MainWindow(QMainWindow):
         
         self.undo_stack.clear()
         self.redo_stack.clear()
+        self.language_overrides.clear()
         
         self.status_label.setText("File closed.")
         QTimer.singleShot(3000, lambda: self.status_label.setText("Ready"))
@@ -770,6 +778,14 @@ class MainWindow(QMainWindow):
         if isinstance(page, Page):
             self.current_page = page
             self.canvas.set_page(page)
+            
+            # Apply session language override if it exists for this page
+            key = (page.magazine, page.page_number)
+            if key in self.language_overrides:
+                self.canvas.subset_idx = self.language_overrides[key]
+                self.canvas.redraw()
+                self.canvas.update()
+                
             self.update_language_label()
             self.canvas.setFocus()