feat: Bootstrap 5 block renderer, widget cards, and sidebar post layout (v1.1.0)

Add BlockRenderer class injecting Bootstrap classes into 8 core block types
(table, button, buttons, image, search, quote, pullquote, list) via per-block
render_block filters using WP_HTML_Tag_Processor.

Add WidgetRenderer class wrapping sidebar widgets in Bootstrap card components
with h4 heading hierarchy via dynamic_sidebar_params and widget_block_content
filters.

Add widget SCSS stylesheet for list styling, search input-group, tag cloud
pills, and card-flush list positioning.

Add single-sidebar.html.twig as the default post template with two-column
Bootstrap layout (col-lg-8 content, col-lg-4 sidebar). Full-width available
via template selection.

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

src/scss/_widgets.scss

@@ -0,0 +1,145 @@
+// Widget Bootstrap 5 styling
+// Targets sidebar widget inner content rendered by WordPress core widgets.
+// Block widgets nest content inside .wp-block-group wrappers.
+
+// Widget headings (block widgets use h4.wp-block-heading after WidgetRenderer transform)
+.widget .card-title,
+.widget .wp-block-heading {
+    margin-bottom: $spacer * 0.75;
+}
+
+// Widget lists (Recent Posts, Archives, Categories, Recent Comments)
+// Covers both legacy (ul direct child) and block widget (ul inside .wp-block-group)
+.widget ul,
+.widget ol {
+    list-style: none;
+    padding-left: 0;
+    margin-bottom: 0;
+
+    li {
+        padding: $list-group-item-padding-y $list-group-item-padding-x;
+        border-bottom: var(--bs-border-width) solid var(--bs-border-color);
+
+        &:last-child {
+            border-bottom: 0;
+        }
+
+        a {
+            text-decoration: none;
+
+            &:hover {
+                text-decoration: underline;
+            }
+        }
+    }
+}
+
+// Flush lists to card edges (negate card-body padding)
+// Handles both direct children and block widget nesting (.wp-block-group > ul)
+.widget .card-body > ul,
+.widget .card-body > ol,
+.widget .card-body > nav > ul,
+.widget .card-body > .wp-block-group > ul,
+.widget .card-body > .wp-block-group > ol {
+    margin: 0 calc(-1 * var(--bs-card-spacer-x)) calc(-1 * var(--bs-card-spacer-y));
+
+    li:first-child {
+        border-top: var(--bs-border-width) solid var(--bs-border-color);
+    }
+}
+
+// Widget select dropdowns (Archives dropdown, Categories dropdown)
+.widget select {
+    display: block;
+    width: 100%;
+    padding: $input-padding-y $input-padding-x;
+    font-size: $input-font-size;
+    line-height: $input-line-height;
+    color: var(--bs-body-color);
+    background-color: var(--bs-body-bg);
+    border: var(--bs-border-width) solid var(--bs-border-color);
+    border-radius: var(--bs-border-radius);
+    appearance: auto;
+    transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
+
+    &:focus {
+        border-color: $input-focus-border-color;
+        outline: 0;
+        box-shadow: $input-focus-box-shadow;
+    }
+}
+
+// Widget search form (legacy get_search_form() widgets)
+.widget .search-form {
+    display: flex;
+    gap: 0.5rem;
+
+    .search-field {
+        flex: 1;
+        display: block;
+        width: 100%;
+        padding: $input-padding-y $input-padding-x;
+        font-size: $input-font-size;
+        line-height: $input-line-height;
+        color: var(--bs-body-color);
+        background-color: var(--bs-body-bg);
+        border: var(--bs-border-width) solid var(--bs-border-color);
+        border-radius: var(--bs-border-radius);
+
+        &:focus {
+            border-color: $input-focus-border-color;
+            outline: 0;
+            box-shadow: $input-focus-box-shadow;
+        }
+    }
+
+    .search-submit {
+        @extend .btn;
+        @extend .btn-primary;
+    }
+}
+
+// Block search widget — hide label, make input-group flush
+.widget .wp-block-search {
+    .wp-block-search__label {
+        display: none;
+    }
+}
+
+// Tag cloud
+.widget .tagcloud {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.375rem;
+
+    a {
+        display: inline-block;
+        padding: 0.25rem 0.5rem;
+        font-size: $font-size-sm !important; // Override inline font-size from WP
+        line-height: 1.5;
+        color: var(--bs-body-color);
+        background-color: var(--bs-tertiary-bg);
+        border: var(--bs-border-width) solid var(--bs-border-color);
+        border-radius: var(--bs-border-radius-pill);
+        text-decoration: none;
+        transition: background-color 0.15s ease-in-out, color 0.15s ease-in-out;
+
+        &:hover {
+            background-color: var(--bs-primary);
+            border-color: var(--bs-primary);
+            color: #fff;
+        }
+    }
+}
+
+// Post date in Recent Posts widget
+.widget .post-date {
+    display: block;
+    font-size: $small-font-size;
+    color: var(--bs-secondary-color);
+}
+
+// Recent Comments styling
+.widget .recentcomments {
+    font-size: $font-size-sm;
+}