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/BinaryOp.php

@@ -0,0 +1,37 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\Node\Expr;
+
+use PhpParser\Node\Expr;
+
+abstract class BinaryOp extends Expr {
+    /** @var Expr The left hand side expression */
+    public Expr $left;
+    /** @var Expr The right hand side expression */
+    public Expr $right;
+
+    /**
+     * Constructs a binary operator node.
+     *
+     * @param Expr $left The left hand side expression
+     * @param Expr $right The right hand side expression
+     * @param array<string, mixed> $attributes Additional attributes
+     */
+    public function __construct(Expr $left, Expr $right, array $attributes = []) {
+        $this->attributes = $attributes;
+        $this->left = $left;
+        $this->right = $right;
+    }
+
+    public function getSubNodeNames(): array {
+        return ['left', 'right'];
+    }
+
+    /**
+     * Get the operator sigil for this binary operation.
+     *
+     * In the case there are multiple possible sigils for an operator, this method does not
+     * necessarily return the one used in the parsed code.
+     */
+    abstract public function getOperatorSigil(): string;
+}