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/Node/Expr/NullsafePropertyFetch.php

@@ -0,0 +1,35 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\Node\Expr;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Identifier;
+
+class NullsafePropertyFetch extends Expr {
+    /** @var Expr Variable holding object */
+    public Expr $var;
+    /** @var Identifier|Expr Property name */
+    public Node $name;
+
+    /**
+     * Constructs a nullsafe property fetch node.
+     *
+     * @param Expr $var Variable holding object
+     * @param string|Identifier|Expr $name Property name
+     * @param array<string, mixed> $attributes Additional attributes
+     */
+    public function __construct(Expr $var, $name, array $attributes = []) {
+        $this->attributes = $attributes;
+        $this->var = $var;
+        $this->name = \is_string($name) ? new Identifier($name) : $name;
+    }
+
+    public function getSubNodeNames(): array {
+        return ['var', 'name'];
+    }
+
+    public function getType(): string {
+        return 'Expr_NullsafePropertyFetch';
+    }
+}