fix(sidebar): collapse empty sidebar column on every scene

Sidebar visibility had two disconnected decisions: the body site-layout-*
class (via aksrt_is_show_sidebar_filter) only checked widget activity for
singles, while the homepage aside renderer skipped the column and
sidebar.php rendered an empty one. With the toggle on and no widgets, the
homepage kept a reserved gutter and squeezed the main content aside.

- collapse every scene to no-sidebar when the sidebar widget stack is empty
- resolve home_sidebar before the page branch so a static front page is
  checked against the zones the homepage renders
- guard the homepage aside with aksrt_is_show_sidebar() alone and drop the
  duplicate aksrt_homepage_has_sidebar gate
- early-return sidebar.php instead of rendering an empty column
- drop dead code: archive helper $preferred param, wp_is_mobile fallback,
  container--no-sidebar class, unreachable front-page fallback
- update post-visual-contract to pin the single visibility decision

Verification: php -l on all changed files; node --test
tests/widget-system/*.test.cjs 242/243 (the toast-contract failure is
pre-existing and unrelated).

inc/helpers/aksrt-archive.php

@@ -122,19 +122,13 @@ if (!function_exists('aksrt_archive_has_sidebar')) :
 	/**
 	 * Resolve whether a stream page should show an aside.
 	 *
-	 * @param string $preferred Preferred sidebar id (compat only).
-	 * @param bool   $enabled   Page-level sidebar toggle.
+	 * @param bool $enabled Page-level sidebar toggle.
 	 */
-	function aksrt_archive_has_sidebar(string $preferred = '', bool $enabled = true): bool {
-		// $preferred kept for call-site compat; visibility is settings/meta driven (legacy).
-		unset($preferred);
+	function aksrt_archive_has_sidebar(bool $enabled = true): bool {
 		if (!$enabled) {
 			return false;
 		}
-		if (function_exists('aksrt_is_show_sidebar')) {
-			return aksrt_is_show_sidebar();
-		}
-		return !wp_is_mobile();
+		return function_exists('aksrt_is_show_sidebar') ? aksrt_is_show_sidebar() : false;
 	}
 endif;
 

inc/helpers/homepage/content.php

@@ -139,35 +139,15 @@ if (!function_exists('aksrt_homepage_render_widget_zone')) {
 	}
 }
 
-if (!function_exists('aksrt_homepage_has_sidebar')) {
-	/**
-	 * Whether the fixed homepage should render an aside column.
-	 */
-	function aksrt_homepage_has_sidebar(): bool {
-		$has_widgets = function_exists('aksrt_has_current_sidebar_widgets')
-			? aksrt_has_current_sidebar_widgets()
-			: aksrt_homepage_has_active_sidebars([
-				'all_sidebar_top',
-				'home_sidebar',
-				'all_sidebar_bottom',
-			]);
-		if (!$has_widgets) {
-			return false;
-		}
-
-		if (function_exists('aksrt_is_show_sidebar')) {
-			return aksrt_is_show_sidebar();
-		}
-		return true;
-	}
-}
-
 if (!function_exists('aksrt_homepage_render_sidebar')) {
 	/**
 	 * Render the homepage aside column.
+	 *
+	 * Visibility is aksrt_is_show_sidebar() alone; its filter already
+	 * collapses the layout when the sidebar widget stack is empty.
 	 */
 	function aksrt_homepage_render_sidebar(): void {
-		if (!aksrt_homepage_has_sidebar()) {
+		if (!aksrt_is_show_sidebar()) {
 			return;
 		}
 

inc/helpers/template-tags/site-layout.php

@@ -41,14 +41,18 @@ function aksrt_resolve_sidebar_id(): string {
         return '';
     }
 
-    if (is_page()) {
-        return 'page_sidebar_' . get_queried_object_id();
-    }
-
+    // The fixed homepage renders home_sidebar for both is_home() and
+    // is_front_page(); a static front page also matches the page branch below,
+    // so this branch must come first to keep visibility checks aligned with
+    // the renderer.
     if (is_home() || is_front_page()) {
         return 'home_sidebar';
     }
 
+    if (is_page()) {
+        return 'page_sidebar_' . get_queried_object_id();
+    }
+
     return 'home_sidebar';
 }
 endif;
@@ -147,7 +151,9 @@ function aksrt_is_show_sidebar_filter(): bool {
         return false;
     }
 
-    if (is_single() && !aksrt_has_current_sidebar_widgets()) {
+    // An empty widget stack would leave the reserved column as a bare gutter,
+    // so every scene (not only singles) collapses to no-sidebar.
+    if (!aksrt_has_current_sidebar_widgets()) {
         return false;
     }