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/ErrorHandler/Collecting.php

@@ -0,0 +1,43 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\ErrorHandler;
+
+use PhpParser\Error;
+use PhpParser\ErrorHandler;
+
+/**
+ * Error handler that collects all errors into an array.
+ *
+ * This allows graceful handling of errors.
+ */
+class Collecting implements ErrorHandler {
+    /** @var Error[] Collected errors */
+    private array $errors = [];
+
+    public function handleError(Error $error): void {
+        $this->errors[] = $error;
+    }
+
+    /**
+     * Get collected errors.
+     *
+     * @return Error[]
+     */
+    public function getErrors(): array {
+        return $this->errors;
+    }
+
+    /**
+     * Check whether there are any errors.
+     */
+    public function hasErrors(): bool {
+        return !empty($this->errors);
+    }
+
+    /**
+     * Reset/clear collected errors.
+     */
+    public function clearErrors(): void {
+        $this->errors = [];
+    }
+}

vendor/nikic/php-parser/lib/PhpParser/ErrorHandler/Throwing.php

@@ -0,0 +1,17 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser\ErrorHandler;
+
+use PhpParser\Error;
+use PhpParser\ErrorHandler;
+
+/**
+ * Error handler that handles all errors by throwing them.
+ *
+ * This is the default strategy used by all components.
+ */
+class Throwing implements ErrorHandler {
+    public function handleError(Error $error): void {
+        throw $error;
+    }
+}