feat(settings): make the settings category list scrollable (#886)

* feat(settings): make the settings category list scrollable

Wrap the sidebar category ListBox in a Gtk.ScrolledWindow (matching the
page wrappers) so the dialog can shrink vertically without clipping
categories and new pages do not pin the minimum window height.

Fixes #678

* fix(settings): reveal the selected sidebar row in the scroller

* fix(settings): retry sidebar scroll until the selected row is laid out

---------

Co-authored-by: Jatin K Malik <jatinkrmalik@gmail.com>

src/vocalinux/ui/settings_dialog.py

@@ -2697,7 +2697,15 @@ class SettingsDialog(Gtk.Dialog):
         for page in self._pages:
             self.sidebar_listbox.add(self._build_sidebar_row(page))
         self.sidebar_listbox.connect("row-selected", self._on_sidebar_row_selected)
-        sidebar_box.pack_start(self.sidebar_listbox, True, True, 0)
+        # Same treatment as the pages: without a ScrolledWindow the category
+        # list's natural height pins the dialog's minimum height, so the
+        # window can never shrink past the list and new categories clip.
+        self.sidebar_scroller = Gtk.ScrolledWindow()
+        self.sidebar_scroller.set_policy(Gtk.PolicyType.NEVER, Gtk.PolicyType.AUTOMATIC)
+        self.sidebar_scroller.set_shadow_type(Gtk.ShadowType.NONE)
+        self.sidebar_scroller.add(self.sidebar_listbox)
+        sidebar_scroller = self.sidebar_scroller
+        sidebar_box.pack_start(sidebar_scroller, True, True, 0)
 
         main_box = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=0)
         main_box.pack_start(sidebar_box, False, False, 0)
@@ -2749,6 +2757,7 @@ class SettingsDialog(Gtk.Dialog):
             self.navigate_to_page(self._initial_page)
         else:
             self.sidebar_listbox.select_row(self.sidebar_listbox.get_row_at_index(0))
+            self._scroll_sidebar_selection_into_view()
 
         # Restore the saved mode and point the simple questions at the live model
         # before the first visibility pass, so nothing flashes the wrong group.
@@ -2773,11 +2782,50 @@ class SettingsDialog(Gtk.Dialog):
     # Navigation: sidebar, stack, and settings search
     # ------------------------------------------------------------------
 
+    def _scroll_sidebar_selection_into_view(self) -> None:
+        """Bring the selected sidebar row into the scroller's viewport."""
+        row = self.sidebar_listbox.get_selected_row()
+        if row is None:
+            return
+
+        def scroll_to_row() -> bool:
+            allocation = row.get_allocation()
+            if allocation.height <= 0:
+                return True  # not laid out yet — try again
+            adjustment = self.sidebar_scroller.get_vadjustment()
+            page_size = adjustment.get_page_size()
+            value = adjustment.get_value()
+            if allocation.y < value:
+                adjustment.set_value(max(adjustment.get_lower(), allocation.y))
+            elif allocation.y + allocation.height > value + page_size:
+                adjustment.set_value(
+                    min(
+                        adjustment.get_upper() - page_size,
+                        allocation.y + allocation.height - page_size,
+                    )
+                )
+            return False
+
+        # Allocations exist only once the row is mapped, which may be after
+        # one idle turn; retry briefly instead of leaving the row hidden.
+        # A new selection aborts the retry for the previously chosen row.
+        retries_left = 20
+
+        def scroll_once() -> bool:
+            nonlocal retries_left
+            retries_left -= 1
+            if self.sidebar_listbox.get_selected_row() is not row:
+                return False
+            return scroll_to_row() and retries_left > 0
+
+        GLib.idle_add(scroll_once)
+
     def navigate_to_page(self, page_name: str) -> bool:
         """Select a settings page by its internal name (e.g. ``about``)."""
         for page in self._pages:
             if page.name == page_name and page.sidebar_row is not None:
                 self.sidebar_listbox.select_row(page.sidebar_row)
+                self._scroll_sidebar_selection_into_view()
                 return True
         return False
 
@@ -2932,6 +2980,7 @@ class SettingsDialog(Gtk.Dialog):
             self._pages[0],
         )
         self.sidebar_listbox.select_row(page.sidebar_row)
+        self._scroll_sidebar_selection_into_view()
         self.settings_stack.set_visible_child_name(page.name)
         self._search_previous_page = None
 
@@ -2996,6 +3045,7 @@ class SettingsDialog(Gtk.Dialog):
 
         if first_match_page is not None:
             self.sidebar_listbox.select_row(first_match_page.sidebar_row)
+            self._scroll_sidebar_selection_into_view()
             self.settings_stack.set_visible_child_name(first_match_page.name)
         else:
             self.sidebar_listbox.unselect_all()