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.

vendor/nikic/php-parser/lib/PhpParser/Builder/Namespace_.php

@@ -0,0 +1,45 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\Builder;
+
+use PhpParser;
+use PhpParser\BuilderHelpers;
+use PhpParser\Node;
+use PhpParser\Node\Stmt;
+
+class Namespace_ extends Declaration {
+    private ?Node\Name $name;
+    /** @var Stmt[] */
+    private array $stmts = [];
+
+    /**
+     * Creates a namespace builder.
+     *
+     * @param Node\Name|string|null $name Name of the namespace
+     */
+    public function __construct($name) {
+        $this->name = null !== $name ? BuilderHelpers::normalizeName($name) : null;
+    }
+
+    /**
+     * Adds a statement.
+     *
+     * @param Node|PhpParser\Builder $stmt The statement to add
+     *
+     * @return $this The builder instance (for fluid interface)
+     */
+    public function addStmt($stmt) {
+        $this->stmts[] = BuilderHelpers::normalizeStmt($stmt);
+
+        return $this;
+    }
+
+    /**
+     * Returns the built node.
+     *
+     * @return Stmt\Namespace_ The built node
+     */
+    public function getNode(): Node {
+        return new Stmt\Namespace_($this->name, $this->stmts, $this->attributes);
+    }
+}