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/NodeFinder.php

@@ -0,0 +1,90 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser;
+
+use PhpParser\NodeVisitor\FindingVisitor;
+use PhpParser\NodeVisitor\FirstFindingVisitor;
+
+class NodeFinder {
+    /**
+     * Find all nodes satisfying a filter callback.
+     *
+     * @param Node|Node[] $nodes Single node or array of nodes to search in
+     * @param callable $filter Filter callback: function(Node $node) : bool
+     *
+     * @return Node[] Found nodes satisfying the filter callback
+     */
+    public function find($nodes, callable $filter): array {
+        if ($nodes === []) {
+            return [];
+        }
+
+        if (!is_array($nodes)) {
+            $nodes = [$nodes];
+        }
+
+        $visitor = new FindingVisitor($filter);
+
+        $traverser = new NodeTraverser($visitor);
+        $traverser->traverse($nodes);
+
+        return $visitor->getFoundNodes();
+    }
+
+    /**
+     * Find all nodes that are instances of a certain class.
+
+     * @template TNode as Node
+     *
+     * @param Node|Node[] $nodes Single node or array of nodes to search in
+     * @param class-string<TNode> $class Class name
+     *
+     * @return TNode[] Found nodes (all instances of $class)
+     */
+    public function findInstanceOf($nodes, string $class): array {
+        return $this->find($nodes, function ($node) use ($class) {
+            return $node instanceof $class;
+        });
+    }
+
+    /**
+     * Find first node satisfying a filter callback.
+     *
+     * @param Node|Node[] $nodes Single node or array of nodes to search in
+     * @param callable $filter Filter callback: function(Node $node) : bool
+     *
+     * @return null|Node Found node (or null if none found)
+     */
+    public function findFirst($nodes, callable $filter): ?Node {
+        if ($nodes === []) {
+            return null;
+        }
+
+        if (!is_array($nodes)) {
+            $nodes = [$nodes];
+        }
+
+        $visitor = new FirstFindingVisitor($filter);
+
+        $traverser = new NodeTraverser($visitor);
+        $traverser->traverse($nodes);
+
+        return $visitor->getFoundNode();
+    }
+
+    /**
+     * Find first node that is an instance of a certain class.
+     *
+     * @template TNode as Node
+     *
+     * @param Node|Node[] $nodes Single node or array of nodes to search in
+     * @param class-string<TNode> $class Class name
+     *
+     * @return null|TNode Found node, which is an instance of $class (or null if none found)
+     */
+    public function findFirstInstanceOf($nodes, string $class): ?Node {
+        return $this->findFirst($nodes, function ($node) use ($class) {
+            return $node instanceof $class;
+        });
+    }
+}