v0.2.0 - Design Editor: templates, patterns, header/footer variations

Full Design Editor compatibility with custom block categories, page templates,
header/footer variations, and navigation styles. Both FSE (admin) and Twig
(frontend) sides kept in sync.

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

templates/page-sidebar.html

@@ -0,0 +1,25 @@
+<!-- wp:template-part {"slug":"header"} /-->
+
+<!-- wp:group {"tagName":"main","style":{"spacing":{"margin":{"top":"var:preset|spacing|60"}}},"layout":{"type":"constrained"}} -->
+<main class="wp-block-group" style="margin-top:var(--wp--preset--spacing--60)">
+    <!-- wp:columns {"align":"wide","style":{"spacing":{"blockGap":{"left":"var:preset|spacing|60"}}}} -->
+    <div class="wp-block-columns alignwide">
+        <!-- wp:column {"width":"66.66%"} -->
+        <div class="wp-block-column" style="flex-basis:66.66%">
+            <!-- wp:post-featured-image {"style":{"spacing":{"margin":{"bottom":"var:preset|spacing|60"}}}} /-->
+            <!-- wp:post-title {"level":1} /-->
+            <!-- wp:post-content {"align":"full","layout":{"type":"constrained"}} /-->
+        </div>
+        <!-- /wp:column -->
+
+        <!-- wp:column {"width":"33.33%"} -->
+        <div class="wp-block-column" style="flex-basis:33.33%">
+            <!-- wp:template-part {"slug":"sidebar"} /-->
+        </div>
+        <!-- /wp:column -->
+    </div>
+    <!-- /wp:columns -->
+</main>
+<!-- /wp:group -->
+
+<!-- wp:template-part {"slug":"footer"} /-->