refactor: Cleanup git state - commit all staged changes

Major refactoring cleanup:
- Add new controller architecture (class-controller-*.php)
- Add new settings-v2 UI (views/settings-v2/)
- Add new CSS architecture (agentic-sidebar.css, tokens)
- Add esbuild build pipeline (scripts/build.js, package.json)
- Add composer dependencies (vendor/)
- Add frontend src directory (assets/js/src/index.jsx)
- Add documentation files
- Remove old/obsolete files (class-settings.php, old CSS)

This commits all pending changes from previous refactoring efforts.

includes/class-controller-config.php

@@ -0,0 +1,104 @@
+<?php
+/**
+ * Config REST Controller
+ *
+ * Handles post configuration operations.
+ *
+ * @package WP_Agentic_Writer
+ */
+
+/**
+ * Class WP_Agentic_Writer_Controller_Config
+ *
+ * REST controller for post configuration operations.
+ *
+ * @since 0.3.0
+ */
+class WP_Agentic_Writer_Controller_Config {
+
+    /**
+     * Sidebar instance for dependency access.
+     *
+     * @var WP_Agentic_Writer_Gutenberg_Sidebar
+     */
+    private $sidebar;
+
+    /**
+     * Constructor.
+     *
+     * @since 0.3.0
+     * @param WP_Agentic_Writer_Gutenberg_Sidebar $sidebar Sidebar instance.
+     */
+    public function __construct( $sidebar ) {
+        $this->sidebar = $sidebar;
+    }
+
+    /**
+     * Handle get post config request.
+     *
+     * @since 0.1.0
+     * @param WP_REST_Request $request REST request.
+     * @return WP_REST_Response|WP_Error
+     */
+    public function handle_get_post_config( $request ) {
+        $post_id = isset( $request['post_id'] ) ? (int) $request['post_id'] : 0;
+        if ( $post_id <= 0 ) {
+            return new WP_Error(
+                'invalid_post',
+                __( 'Invalid post ID.', 'wp-agentic-writer' ),
+                [ 'status' => 400 ],
+            );
+        }
+
+        if ( ! $this->sidebar->check_post_permission( $post_id ) ) {
+            return new WP_Error(
+                'forbidden',
+                __(
+                    'You do not have permission to access this post.',
+                    'wp-agentic-writer',
+                ),
+                [ 'status' => 403 ],
+            );
+        }
+
+        return new WP_REST_Response( $this->sidebar->get_post_config( $post_id ), 200 );
+    }
+
+    /**
+     * Handle update post config request.
+     *
+     * @since 0.1.0
+     * @param WP_REST_Request $request REST request.
+     * @return WP_REST_Response|WP_Error
+     */
+    public function handle_update_post_config( $request ) {
+        $post_id = isset( $request['post_id'] ) ? (int) $request['post_id'] : 0;
+        if ( $post_id <= 0 ) {
+            return new WP_Error(
+                'invalid_post',
+                __( 'Invalid post ID.', 'wp-agentic-writer' ),
+                [ 'status' => 400 ],
+            );
+        }
+
+        if ( ! $this->sidebar->check_post_permission( $post_id ) ) {
+            return new WP_Error(
+                'forbidden',
+                __(
+                    'You do not have permission to edit this post.',
+                    'wp-agentic-writer',
+                ),
+                [ 'status' => 403 ],
+            );
+        }
+
+        $params = $request->get_json_params();
+        $config = $this->sidebar->sanitize_post_config( $params['postConfig'] ?? [] );
+        update_post_meta( $post_id, '_wpaw_post_config', $config );
+
+        // MEMANTO: Store config preference.
+        do_action( 'wpaw_memanto_config_saved', $post_id, $config );
+
+        return new WP_REST_Response( $config, 200 );
+    }
+}