ui: sidebar tab selector uses text labels instead of icons

The two drawn tab glyphs were judged not understandable enough; the
switcher goes to the wide policy with titles only, and the glyphs,
their gresource entries and the icon-naming code are removed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/ui_app.hpp

@@ -440,21 +440,13 @@ struct App {
   /// works, and every other line of the dump still passes.
   std::string dbg_toolbar_icons;
   std::string dbg_app_icons;
-  /// The two sidebar pages' own icons and whether the theme resolved them, read on the first tick
-  /// like the two lines above.
-  std::string dbg_page_icons;
-  /// What the switcher is: how many pills it holds, and how many labels it is *drawing*. The label
-  /// count is the one that says the pages are icons rather than words: `narrow` hides them, and the
-  /// titles stay set because they are the pages' names for a screen reader and for the tooltip.
+  /// What the switcher is: how many pills it holds, and how many labels it is *drawing*. The tabs
+  /// are words (`wide` policy, a title per page), so the label count must equal the page count.
   int dbg_switcher_pills = -1;
   int dbg_switcher_labels = -1;
-  int dbg_switcher_names = -1;
-  /// The pills' icon as it is *rendered*: a 32x16 glyph in a 32px box is drawn 1:1, which is what
-  /// keeps its 2px bars crisp.
-  int dbg_switcher_icon_w = -1;
-  int dbg_switcher_icon_h = -1;
-  /// The switcher's own size, beside it: the pills carry 32px icon boxes now, so the tab bar's height
-  /// is what it costs.
+  /// How many pages the sidebar stack holds: `pills` and `labels` must both equal it.
+  int dbg_switcher_pages = -1;
+  /// The switcher's own size, beside it: what the tab bar costs the column.
   int dbg_switcher_w = -1;
   int dbg_switcher_h = -1;
   /// The panes' own switches and the header bar's buttons, read together by the exit probe: the two
@@ -473,8 +465,6 @@ struct App {
   /// thing in the body that *is* disabled with the mode.
   int dbg_arm_sensitive = -1;
   int dbg_switcher_policy = -1;
-  /// Whether `name_side_tabs()` has named the pills: it can only run once the switcher is mapped.
-  bool side_tabs_named = false;
   /// The header bar, so the dump can report the order the controls are in: a header bar is a
   /// *titlebar*, not a child of the window, so walking down from the window does not reach it.
   GtkWidget* toolbar = nullptr;