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.

phpunit.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.6/phpunit.xsd"
+         bootstrap="tests/bootstrap.php"
+         colors="true"
+         cacheResult="false"
+         executionOrder="depends,defects"
+         beStrictAboutOutputDuringTests="true"
+         beStrictAboutTodoAnnotatedTests="true"
+         failOnRisky="true"
+         failOnWarning="true">
+    <testsuites>
+        <testsuite name="Unit Tests">
+            <directory suffix=".php">tests/</directory>
+            <exclude>tests/bootstrap.php</exclude>
+        </testsuite>
+    </testsuites>
+    <coverage processUncoveredFiles="true">
+        <include>
+            <directory suffix=".php">includes/</directory>
+        </include>
+        <exclude>
+            <file>includes/class-gutenberg-sidebar.php</file>
+            <file>includes/class-sidebar-helpers.php</file>
+        </exclude>
+    </coverage>
+    <php>
+        <const name="WPAW_PLUGIN_DIR" value="/Users/dwindown/Local Sites/bricks/app/public/wp-content/plugins/wp-agentic-writer/"/>
+        <const name="WP_AGENTIC_WRITER_URL" value="http://localhost/"/>
+        <env name="SCRIPT_DEBUG" value="1"/>
+    </php>
+</phpunit>