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/Parser.php

@@ -0,0 +1,24 @@
+<?php declare(strict_types=1);
+
+namespace PhpParser;
+
+interface Parser {
+    /**
+     * Parses PHP code into a node tree.
+     *
+     * @param string $code The source code to parse
+     * @param ErrorHandler|null $errorHandler Error handler to use for lexer/parser errors, defaults
+     *                                        to ErrorHandler\Throwing.
+     *
+     * @return Node\Stmt[]|null Array of statements (or null non-throwing error handler is used and
+     *                          the parser was unable to recover from an error).
+     */
+    public function parse(string $code, ?ErrorHandler $errorHandler = null): ?array;
+
+    /**
+     * Return tokens for the last parse.
+     *
+     * @return Token[]
+     */
+    public function getTokens(): array;
+}